So... someone graciously donated an engine to me, and I was under the impression that we were going to be able to convert my daughter's 1985 2.5 Iron Duke to the belt tensioner / serpentine system, and possibly even install a harmonic balancer, rather than use the old-school V-belt system which... well... basically sucks.
She's away on an orchestra trip, so I snuck a peak and removed the belt tensioner... only to realize that the three bolts that hold it on actually do go into the block itself, and not the brackets. On the 1984-1986 engine, there is a "block-off" plate to cover up where the water pump would normally go in a traditional "longitudinally" mounted version of the Iron Duke... you know, where the fan bolts to the waterpump pulley in a clutch-system. In any case, the block off plate used in the 84-86 Fieros is attached using 4 fine-threat machine bolts.
On the 1987-1988 Fiero duke engines, it's attached using 3 much larger fine-threat machine bolts. It essentially takes the place of the block-off plate and itself functions AS the block-off plate.
There's only ONE bolt that lines up, and that's the one in the upper-right hand corner, which COULD be drilled and re-tapped to the larger thread size. Unfortunately, they reinforced the block for this, and added more "meat" to the block in order to support this larger hole. The other two bolts are in a completely different spot.
Some thoughts I had is that I could have the factory tensioner machined down so that I could keep the factory block-off plate (which has the timing hole), and perhaps then just drill holes in the factory tensioner bracket... and use the existing bolt holes. All of that WOULD work, however, the concern then is... would those four (smaller) machine bolts be able to support the torque / stress of the belt tensioner. My thought is NO.
Now, I've NOT given up hope, yet... my thoughts are this, I could have someone make a 1/8th inch plate that would connect the factory (1987) bracket to the water-pump bracket on the other side, and even have it connect to the lower A/C compressor bracket (1987) where it attaches.. This would provide the major support needed for a belt tensioner. We could simply weld a nut on the top where the belt tensioner pulley goes into. For the sake of using those extra bolts, four holes could be drilled into this plate in order for the factory 1984-1985 blockoff plate bolts to go through.
I'm thinking this wouldn't be a huge undertaking. I'd need to fabricate something in cardboard, and then find a place that would be willing to cut it out for me. Or... I could simply just buy some flat stock, and then buy a metal cutting band saw and do it myself.
Thoughts?
I know there's the... "not worth it," but let me tell you... I've had 3-4 Iron Dukes, and I cannot stand V-belts.
EDIT: to say that for those who don't know... the block off plate on the 84-86 has four bolts, but these bolts are basically double-ended. So there's bolts with a nut, and then bolts coming out the other end. The point of this is because there's a plastic bracket (and some other things), that attach to it. In the 87-88 model years, they re-routed most of the electrical wiring in the car to go along the back, rather than have the wiring go down the front of the motor (to go to the A/C and a few other things). So I would be re-routing it anyway, and would not be using this plastic bracket anyway.
[This message has been edited by 82-T/A [At Work] (edited 04-06-2024).]
When people "hate V belts" is a problem w/ the setup or more likely problem w/ the Installer cause Too Tight or Too Loose & belt suffers in Seconds.
You "hate V belts" yet have no clue about serpents on Dukes in Fiero & other Model Lines...
1. Doubt the tensioner arm is actually good & likely not finding a new replacement. Bad Arm = Belt Track is Off &/or Belt Tension is uneven across the width. TFS "cornered the market" for Fiero Tensioner & help jack up the price to 2x 3x & more. RD tried to sell a mod to other tensioner to fit Fiero for this reason but had issues too.
2. Has AC? Good luck finding a compressor & brackets to do this. AC pulley Must be in line w/ all other & exact alignment or Belt will Fail & Fast because 3 pulleys w/o space to try to handle even smallest alignment problem. Have worse Alignment problems after messing w/ WP & its pulley because issues there...
Even W/O AC or Bypassing AC, WP pulley must have Alignment Check because replacing it changes Tolerance Stacking that can Effect Pulley Alignment enough to cause Belt Wear even when have longer belt section between pulleys.
3. Finding Serpent w/ right size often isn't easy now. Even w/ OE setup on 87-88 Fiero dukes w/ OE PN current Belts from any brand have problems, worse on AC, because OE tensioner have a Very Narrow on Belt Size & Too long = slips, too short & tensioner breaks. All in aftermarket said somewhere that Printed Size/Spec is Not Exact belt size. Change Brand/Model is bad enough but even buying a belt today is not exact same as old belt or belt you get next year even from same brand etc.
Plus most or all belt makers change the "rubber" type to EPDM so now the serpents often make No Noise while they die.
see cave, serpent belt shares many problems w/ V but adds own problems.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
When people "hate V belts" is a problem w/ the setup or more likely problem w/ the Installer cause Too Tight or Too Loose & belt suffers in Seconds.
You "hate V belts" yet have no clue about serpents on Dukes in Fiero & other Model Lines...
1. Doubt the tensioner arm is actually good & likely not finding a new replacement. Bad Arm = Belt Track is Off &/or Belt Tension is uneven across the width. TFS "cornered the market" for Fiero Tensioner & help jack up the price to 2x 3x & more. RD tried to sell a mod to other tensioner to fit Fiero for this reason but had issues too.
2. Has AC? Good luck finding a compressor & brackets to do this. AC pulley Must be in line w/ all other & exact alignment or Belt will Fail & Fast because 3 pulleys w/o space to try to handle even smallest alignment problem. Have worse Alignment problems after messing w/ WP & its pulley because issues there...
Even W/O AC or Bypassing AC, WP pulley must have Alignment Check because replacing it changes Tolerance Stacking that can Effect Pulley Alignment enough to cause Belt Wear even when have longer belt section between pulleys.
3. Finding Serpent w/ right size often isn't easy now. Even w/ OE setup on 87-88 Fiero dukes w/ OE PN current Belts from any brand have problems, worse on AC, because OE tensioner have a Very Narrow on Belt Size & Too long = slips, too short & tensioner breaks. All in aftermarket said somewhere that Printed Size/Spec is Not Exact belt size. Change Brand/Model is bad enough but even buying a belt today is not exact same as old belt or belt you get next year even from same brand etc.
Plus most or all belt makers change the "rubber" type to EPDM so now the serpents often make No Noise while they die.
see cave, serpent belt shares many problems w/ V but adds own problems.
Hi Ogre,
#1 - I have a good original (tensioner is still good), and I also bought the Rodney Dickman replacement tensioner (never used).
#2 - I have a complete 1988 Iron Duke with all the accessories installed. I plan on swapping everything over. From what I can tell, everything from the 88 will swap onto the 85, with exception... - The tensioner (obviously, as mentioned above) - A small alternator support bar that connects the back of the alternator to the intake manifold. This will need to be bent at a 90 degree angle as the intakes are different from 86-87.
BUT... there's a possibility that I actually don't have a tensioner at all, and instead... this bracket I make, all I do is merely install an "idler" pulley. I can actually KEEP the alternator bracket from the 1985, go with the newer alternator and serpentine pulley, and then simply use the alternator as the adjustment.
EDIT: I'm planning on also upgrading to the newer 86+ compressor system. If I need to, I will upgrade to the later 1986 2m4 ECM.
[This message has been edited by 82-T/A [At Work] (edited 04-06-2024).]
So, I'm going to update this, and I'll have my daughter make a video on it. But so far, here is what I've determined...
1 - The factory belt tensioner from 1987-1988 will NOT bolt up to a 1986 and older engine block. The bolt holes are substantially different, and in a different location.
2 - Everything on the "right" side of the engine (forward part of the motor when installed), will bolt up the same from 1984-1988.
3 - Everything on the "left" side of the engine (rear part of the motor when installed), will bolt up to the head and block, but requires modification because the intakes are different.
4 - Crank hubs are different. It doesn't seem like the 88 pulley bolts on to anything, so much as it's held in place by the crank bolt.
- BREAK -
I have some options. One, someone would need to make a custom belt tensioner bracket... but these brackets are really thick, and need to be able to properly support the stress of the belt system. Two, I could eliminate the belt tensioner system all together, and instead, simply install an Idler pulley somewhere on the front, and then I can simply use the serpentine belt system, but use the 84-86 alternator bracket, with the new C130 alternator... which is adjustable for the belt tension. This way, I can switch to a serpentine system, get the benefits of a "single belt" system, use the newer compressor, newer alternator, AND be able to use a harmonic balancer, while still being able to use the original coolant block-off plate with the timing hole.
The ONLY thing I'll need to fabricate, will be the idler pulley, and then determine the best belt length for the system.
Serpentine belt is far superior to V Belts which is why you do not see modern cars with V belts. It comes down to is the cost of the 2.5l belt tensioner worth it to you?
[This message has been edited by jelly2m8 (edited 04-08-2024).]
Serpentine belt is far superior to V Belts which is why you do not see modern cars with V belts. It comes down to is the cost of the 2.5l belt tensioner worth it to you?
I agree... I'm dead-set on getting a working serpentine system for my daughter's duke.
I think I've settled on the idea of getting an idler pulley, and continuing to use the alternator as the adjustment point for belt tension. Technically, without anything else, I'd be able to use the serpentine belt system, it just wouldn't be much of a serpentine system, so I just need to figure out the right placement for an idler pulley.
I realize this is for the V6, and I already have the idler pulley on my V6 (which works really well), but I figured I could kill two birds with one purchase here... I don't have the newer underdrive pulleys for my V6 (which this kit comes with), and I figured I could use the new Idler pulley here for my daughter's Iron Duke. If need be, I can simply cut / weld it into a larger bracket that I make. I already ordered a flat stock of 1/4" plate steel, which I intend to cut into a bracket. So we'll see... I want something that is the absolute least complicated, but that is also reliable. My hope is that it's something I can then simply give my plans to Rodney for free, and maybe if interested, he can make a bunch of them for other people.
What I'm looking at now... EVERYTHING is available off the shelf "except" the idler pulley bracket. You can order a new C-130 alternator that already has the new pulley and will work with the factory brackets. You can also order a new water pump that also already has the new pulley installed. You can also buy a serpentine crank pulley off eBay from any number of other years, and then... finally, for the A/C compressor, if you want to convert to the newer V5 compressor, you just need the brackets from a factory Fiero, OR... you can still also buy the DA6 compressor with the serpentine belt pulley as well.
So other than replacing your alternator, water pump, and compressor, the only thing you'd actually need is the idler pulley bracket and the correct belt length.
So, just resurrecting this thread to add some updates. The belt tensioner I got from Rodney is a bust. I have a new tensioner, but the actual engine block is completely different. The factory 87-88 belt tensioner replaces the "water block off plate" that's on the front of the Iron Duke engine. In the "old days" this block off plate is where the water pump would have mounted to.
In the 84-86 engines, there's four smaller bolts, and in the 87-88 there are three LARGE bolts. The bosses don't exist, so you couldn't even drill and tap for them in the 84-86... the meat just isn't there in block for you to do it. So, that's no longer an option.
I've come to the conclusion though that you can actually still have the serpentine belt system, but without the tensioner, by using a combination of parts from the 86- and 87+ ...
1 - Use the whole "right side" of the engine from the 87, including water pump with 6-groove pulley, and A/C compressor brackets and pulley. 2 - Use the 87+ alternator with the serpentine 6-groove pulley, BUT... use the alternator bracket from the 84-86 engine. You'll essentially use the alternator to provide the tension on the engine. 3 - Use the crank hub and pulley from the 87+
I'm looking to see if there's a place where we might be able to add an Idler Pulley... I have a few thoughts, but my daughter will need to get everything put together first.
The one thing the tensioner does (other than creating tension), is it increases the surface area of the pulley that the belt will come in contact with. With the tensioner off... you're losing some of that surface area on the crank pulley and the alternator pulley. It's not significant, mind you... but with an idler pulley installed somewhere ... ideally close to the factory tensioner location, will help. I may have to make my own bracket, but we'll see.
In the mean time, I bought a new hub / pulley that has an integrated harmonic balancer... so I'm also hoping (at the same time) to smooth out the engine a little bit.
The crank pulley will "eat" the S-belt w/o the tensioner. W/ or W/O adding AC but way faster W/ AC because crank pulley only has maybe 1/8 wrap of total circumference of that pulley.
Needs 1/3 pulley wrap of the crank pulley @ minimum to take the load to drive all others. Even ~ 1/4 pulley wrap on WP & AC on 87+ dukes causes problems that eats the belt because AC can put huge loads when V5 Compressor is @ Max Displacement or have any other problems.
IOW you will have Same or even Worse belt problems as V6 & why they push adding idle pulley or tensioner. And you can't the V6 idle pulley even if you can fit one because crank pulley belt wrap is still < 1/3.
That even when you have 100% Accurate Pulley Alignment that very likely you're not going to get. Example: I had a WP replace on 87 Duke & shop didn't align the pulley & ate belts until I borrowed a very expensive laser tool to align WP AC & Crank pulley & even then Very Hard to align because super short of belt span between them & need 98+% actuate. Even w/ AC bypass belt so belt has bigger span, belts wear fast any misalignment & newer belts often doesn't make nose to warn you before Failing COMPLETELY.
Leave the V belts alone & use a Krikit to set Belt Tension. 90+% problems w/ V are cause by morons installing them too tight or too loose. Krikit solves this & is cheap. Way cheaper then full belt tension tools that even most shops don't have.
Adding harmonic balancer Does Nothing that you can hear or feel. Only Helps 1 set of vibration types that is part of why the OEM Fiber Cam Gear Fails. Other Big Problems for all Pre DIS are Oil Pump &/or Distributor often have problems then Over Loaded the Fiber gear but most never bother even to check then & blame the cam gear when "fails" again.
The crank pulley will "eat" the S-belt w/o the tensioner. W/ or W/O adding AC but way faster W/ AC because crank pulley only has maybe 1/8 wrap of total circumference of that pulley.
Needs 1/3 pulley wrap of the crank pulley @ minimum to take the load to drive all others. Even ~ 1/4 pulley wrap on WP & AC on 87+ dukes causes problems that eats the belt because AC can put huge loads when V5 Compressor is @ Max Displacement or have any other problems.
IOW you will have Same or even Worse belt problems as V6 & why they push adding idle pulley or tensioner. And you can't the V6 idle pulley even if you can fit one because crank pulley belt wrap is still < 1/3.
That even when you have 100% Accurate Pulley Alignment that very likely you're not going to get. Example: I had a WP replace on 87 Duke & shop didn't align the pulley & ate belts until I borrowed a very expensive laser tool to align WP AC & Crank pulley & even then Very Hard to align because super short of belt span between them & need 98+% actuate. Even w/ AC bypass belt so belt has bigger span, belts wear fast any misalignment & newer belts often doesn't make nose to warn you before Failing COMPLETELY.
Leave the V belts alone & use a Krikit to set Belt Tension. 90+% problems w/ V are cause by morons installing them too tight or too loose. Krikit solves this & is cheap. Way cheaper then full belt tension tools that even most shops don't have.
Adding harmonic balancer Does Nothing that you can hear or feel. Only Helps 1 set of vibration types that is part of why the OEM Fiber Cam Gear Fails. Other Big Problems for all Pre DIS are Oil Pump &/or Distributor often have problems then Over Loaded the Fiber gear but most never bother even to check then & blame the cam gear when "fails" again.
a. 1993 and 1994 honda f series engines have manual tensioners on the alternator and power steering pump (2 different serpentine belts b.yes they need at least one third. unless its a v6 mustang apparently. that has less than a quarter engagement on its factory ac and alternator c. no you don't need perfect alignment (source is my buddies engine swapped cb7 accord that has 5 different pulleys and had its belt aligned with a bent yardstick.) d. he could do v-belts but why? if he manages this then it opens up loads of options for things we can do to these early engines like I dunno. a belt driven supercharger that mounts inplace of the ac or something similar e. technically correct? I've never had a Fiber gear break on anything not even my million mile ford 300 with its factory gear so as long as the balancer actually does balance the rotating assembly correctly it's not really gonna hurt anything.
I do agree v belts would be easier for legitimately 99% of people and personally i love using them, but it would be cool to bring these cars into the late 90s of technology wouldn't it?
The crank pulley will "eat" the S-belt w/o the tensioner. W/ or W/O adding AC but way faster W/ AC because crank pulley only has maybe 1/8 wrap of total circumference of that pulley.
Needs 1/3 pulley wrap of the crank pulley @ minimum to take the load to drive all others. Even ~ 1/4 pulley wrap on WP & AC on 87+ dukes causes problems that eats the belt because AC can put huge loads when V5 Compressor is @ Max Displacement or have any other problems.
IOW you will have Same or even Worse belt problems as V6 & why they push adding idle pulley or tensioner. And you can't the V6 idle pulley even if you can fit one because crank pulley belt wrap is still < 1/3.
Thanks Ogre, I agree... it's not ideal. As it would be right now... the belt path is the same as the V-belt, with a slight deviation because the A/C is now driven by the serpentine, rather than by its own V-belt. So this removes a little more surface area. I'm still getting about 1/3rd, but now how I intend to leave it. I bought another V6 idler pulley from Rodney. My daughter and I need to get all the accessories on the engine so that I can get a better idea of where I can possibly place an idler pulley. It will likely be in the same location as the factory belt tensioner, but I'm going to have to make a bracket, or look to see if there's a single stud somewhere that I can have a longer bolt with a spacer and idler pulley attached. I have to see how everything comes together.
quote
Originally posted by theogre:Leave the V belts alone & use a Krikit to set Belt Tension.
You're giving me stress here, and flashbacks to when I had to set the belt tension on my Porsche 944's timing belt.
quote
Originally posted by theogre:Adding harmonic balancer Does Nothing that you can hear or feel. Only Helps 1 set of vibration types that is part of why the OEM Fiber Cam Gear Fails. Other Big Problems for all Pre DIS are Oil Pump &/or Distributor often have problems then Over Loaded the Fiber gear but most never bother even to check then & blame the cam gear when "fails" again.
Thanks Ogre... I got the part numbers for the harmonic balancer off your Cave. I've never had a fiber gear fail... and the one we took off was actually pretty decent after 150k miles. She ended up going with a new Cloyes Aluminum timing gear set (crank pulley is steel). I'm not sure how I feel about aluminum... but I'm assuming it has to be at least as strong as the fiber one... otherwise why would they even be selling it.
We did go with a larger volume oil pump, a Melling M62CHV w/ new pickup. I don't expect her engine will sound any different (it didn't actually sound too bad before we tore it down), I just want to build it in a way that it's the most reliable and durable, and easiest to work on and fix should she need to do something in a pinch. A single serpentine is just so much easier in that regard.
quote
Originally posted by cartercarbaficionado:
a. 1993 and 1994 honda f series engines have manual tensioners on the alternator and power steering pump (2 different serpentine belts b.yes they need at least one third. unless its a v6 mustang apparently. that has less than a quarter engagement on its factory ac and alternator c. no you don't need perfect alignment (source is my buddies engine swapped cb7 accord that has 5 different pulleys and had its belt aligned with a bent yardstick.) d. he could do v-belts but why? if he manages this then it opens up loads of options for things we can do to these early engines like I dunno. a belt driven supercharger that mounts inplace of the ac or something similar
I do agree v belts would be easier for legitimately 99% of people and personally i love using them, but it would be cool to bring these cars into the late 90s of technology wouldn't it?
Yeah, I'm thinking the benefits outweigh the negatives. General Motors clearly thought this was a benefit, as they quickly replaced the whole belt system in the Fiero by 87 for the 4 cyl. To that point, they added the A/C compressor to a single belt also. Without the tensioner, I'm not really losing very much on the crank pulley... almost negligible, but I am on the alternator, which I think may be an issue. But my goal is still to find a place to mount an Idler pulley. And you're right, an adjustable alternator is perfectly fine for serpentine belt tensioning... this is anyway, how it's done on the V6 Fiero with a serpentine system.
Just thought I'd update this thread with the latest stuff we've done...
My daughter got all the accessories on the engine today. It's been slow going, just a lot going on... but she got the new alternator, new starter, cleaned up water pump pulley (with new water pump), and the new A/C compressor installed... all with the correct brackets.
I don't know why these pictures came out so badly... but whatever...
Again, if I didn't mention it, this is a 1985 roller-cam block that we're converting to a serpentine system:
ALTERNATOR - Alternator comes from a 1988 Fiero V6, with a 6-groove 1987-1988 L4 Fiero alternator pulley. We use the alternator brackets from the 1984-1986 Fiero engine.
AC COMPRESSOR - We use an A/C compressor from a 1987-1988 L4 Fiero, specifically with a 6-groove serpentine pulley. Brackets come from an 87-88 Fiero. There's one bolt hole missing from the bracket, but it still bolts in perfectly. It really feels like it doesn't need it, but I may weld an "ear" on the bracket to use the other bolt hole (block differences from 1985 and 1988). We can't use the 86 bracket because even though it uses the new compressor, we want to convert to a serpentine system, and the 86 brackets are designed to allow the compressor to be adjusted for belt tension (has a separate belt).
WATERPUMP - There is no difference on the waterpumps for the Fiero from 1984-1988. The only difference is the pulley. The biggest issue is that the pulley is extremely hard to find. This one was given to me off a donor L4 / 87 motor. The one from my 88 was very badly mangled and we couldn't use it.
CRANK PULLEY - The crank pulley from a 1987-1988 Fiero L4 will easily fit a 1984-1986 crank... and it'll just work. But we wanted to incorporate a harmonic balancer to help smooth out the motor a little bit. We found a brand new OEM GM one that was compatible (from like a 1989 Grand Am), and installed it. NOTE: L4 Fieros never came with a harmonic balancer.
She also installed a new starter, which is the much smaller starter from the 3400 V6 in the 1998 Pontiac Grand Am ? (if I remember correctly).
... as you can see, the only bad thing is that you don't get a lot of contact surface on the crank pulley. I don't think it will be a huge issue... particularly because to be quite honest, this is the factory belt routing of the normal "V" belt, which tends to have less grip anyway. It's not ideal... the V-belt L4 Fieros always seemed to squeal. The 87-88 Fieros used a belt tensioner which really improved the contact pattern, and I don't think this was ever an issue for those cars. I'll say in this case, it's a 6-groove pulley (everything is 6-groove) and the V6 Fiero (which does not have a tensioner) is only a 5-groove. So I THINK I'm going to be OK. I'm still looking for potentially a spot to place an idler pulley.
As I mentioned before, the factory belt tensioner will not fit on the 84-86 blocks... the bolt locations just aren't there. GM changed a lot of stuff from 86-87... and that being one of them. The whole block is totally different, so it's amazing that anything bolts up (as you see above).
Just floating some ideas, but I'm thinking either an idler pulley sitting somewhere between the waterpump, compressor, and crank pulley... like, right in the middle of that triangle, so after it goes around the waterpump and compressor, it then sneaks up to an idler pulley, and then back down to wrap around the crank pulley before going back up to the alternator. It gives a bit more meet on the crank pulley... and I could install a stud there... but I may not even need it... so still considering.
[This message has been edited by 82-T/A [At Work] (edited 06-09-2024).]
Just floating some ideas, but I'm thinking either an idler pulley sitting somewhere...
...between the crank pulley and the alternator would be my first choice. I believe it's best to have a tensioner/idler pulley located immediately after the driving (crank) pulley, as is demonstrated in this image of Dodgerunner's tensioner on a 2.8 V6.
...between the crank pulley and the alternator would be my first choice. I believe it's best to have a tensioner/idler pulley located immediately after the driving (crank) pulley, as is demonstrated in this image of Dodgerunner's tensioner on a 2.8 V6.
That's a pretty nice set-up he has, but I'm trying to resist having to make a huge crazy bracket to properly support it. Ideally, I'm looking for something where I can simply have an idler pulley. I don't really need / want a belt tensioner. I think for these engines (lower RPMs), it doesn't make a whole ton of sense. GM clearly thought to put one in, but I can't place it in the factory location. There's a power steering delete bracket with a huge 6-groove pulley that has a single bolt mount in the middle... I could conceivably drill and tap a hole in the alternator bracket (bottom part)... I dunno. I may even wait until I've got the engine in and see how it performs before I try to fabricate something.
I'm still looking though. I want her to get everything installed on the engine so I know what I have access to and where I can possibly make some change.
Ideally, I'm looking for something where I can simply have an idler pulley. I don't really need / want a belt tensioner.
I wasn't promoting the use of a tensioner (although it is superior than a simple idler pulley). I was more indicating the ideal location for an idler (and/or tensioner).
[This message has been edited by Patrick (edited 06-10-2024).]
I wasn't promoting the use of a tensioner (although it is superior than a simple idler pulley). I was more indicating the ideal location for an idler (and/or tensioner).
Sorry... I was more thinking than responding. I definitely got that from your response (also)... so definitely noted. It seems also that might be the only place I'll be able to put one.
So, some bad news in case anyone else with an Iron Duke is looking to upgrade to a harmonic balancer. But apparently there are no new companies producing this harmonic balancer anymore. I just got an e-mail from Summit Racing, with whom I've had an order for a replacement DORMAN RNB-594-027 balancer. The company had intended to reproduce them, but ultimately just decided there wasn't enough interest.
The one I got above was an original GM one that I just got dumb-lucky with.
But there are several places that REBUILD harmonic-balancers... so keep the one you have (if you have one).
