most of the syclone guys are getting from 400 to 600 hp from 4.3....

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84 Fiero Turbo Vortec 4300 Phantom GT
L35 block
Syclone Intake and ECM
T04B H3 Turbo
http://www.cardomain.com/id/vortecfiero

"Any significantly advanced technology is indistinguishable from magic"

tony-c email me those pics!!!!!!!!!!!!
thanks!
tonypaul@fastestcar.com

cardealer..u have mail

Will,
I never said the olds/caddy engine were the same thing. Both engines were mounted to the same transmissiion and put in similar cars. I have built and raced several 350 and 455 olds. For their size and weight they will not compete with a sbc/bbc. The olds heads are poorly designed and do not breathe well. In all fairness if olds had been developed as much as the sbc I'm sure it would be much better. The sbc has mountains of performance parts available at very low cost. It's been 15 years since I built any olds. They are antiques. It's getting hard and expensive to get 425 transmissions and parts. As I remember there were no performance parts for the caddy. I've never tried it but it looks to me that the later downsized caddy fwd trans would work well. Don't remember the model designation. It bolts to a sbc and is smaller. Oh by the way, the 425 trans is very inefficient. That huge chain in there sucks a bunch of power. That's the reason the more modern fwd transmissions run the engine parallel to the axle. That chain and the bevel gears in the diff really hurt efficiency.
If you really want to do this I suggest you use the Holley Vari-jection. The last 455 olds I built actually passed the emissions test for a chevy 350 and it had no converter on it. Good luck whatever you do.
Larry

quote Originally posted by larryemory: Will, I never said the olds/caddy engine were the same thing. Both engines were mounted to the same transmissiion and put in similar cars. I have built and raced several 350 and 455 olds. For their size and weight they will not compete with a sbc/bbc. The olds heads are poorly designed and do not breathe well. In all fairness if olds had been developed as much as the sbc I'm sure it would be much better. The sbc has mountains of performance parts available at very low cost. It's been 15 years since I built any olds. They are antiques. It's getting hard and expensive to get 425 transmissions and parts. As I remember there were no performance parts for the caddy. I've never tried it but it looks to me that the later downsized caddy fwd trans would work well. Don't remember the model designation. It bolts to a sbc and is smaller. Oh by the way, the 425 trans is very inefficient. That huge chain in there sucks a bunch of power. That's the reason the more modern fwd transmissions run the engine parallel to the axle. That chain and the bevel gears in the diff really hurt efficiency. If you really want to do this I suggest you use the Holley Vari-jection. The last 455 olds I built actually passed the emissions test for a chevy 350 and it had no converter on it. Good luck whatever you do. Larry

larry you seem to be a nice and caring person but many of your facts/information may not be correct. i can show some dyno charts of sbc & bbc vs. bbo that might suprise you. the 455s weight less than a bbc. the "later downsized caddy fwd tranny" doesnt bolt to a sbc. the 425 trans is not " very inefficient" do to the "huge" chain. the gear ratio is what many people have refered as being lacking to produce measurable power, but that can be corrected. during this thread "efficiency" has never been the topic and there is no "bevel gears" in a 8 bolt final drive. the 425 trans is the only trans i have found that can hold the torque, provide a better stall, better gear ratio for the money. the 425's and the parts are not expensive and hard to get its the good final drives are the problem. engines are not running parallel to the axle due to the "huge chain", its due to the fact that the modern fwd trans dont have to have a big chain to support 400hp and 500fpt big engines. dont take this the wrong way!!!!!! i just thought i would add some points to your post in hope of keeping others opinons open.
good luck

thanks guys, what i was thinking to do, was pull the entire engine cradle out and build it in my garage, that way i can make sure it will it work.

Cardealer.....your mailbox was full..I re-sent it

Thanks, Cardealer for your response. If I did make incorrect statements I expect them to be corrected. No offense will be taken. The purpose of this forum is to disseminate correct information. I do not beleive I made any incorrect statements. My comparisons of olds/chevy refer to my personal experiences in racing in several types and divisions of racing. I know in racing both big & small block olds I could not make as much power as the chevys. Most of us do not have dynos to find the best combination. I'm reasonably certain that my competitors didn't have dynos either. As far as the later caddy fwd trans is concerned, I can't find my books to verify what I said. Remember when GM introduced the "corperate" v8 engine and was promptly sued for putting chevy engines in Buicks, Pontiacs, & Olds. I still think that is what happened here. I can't prove it but it sure looks like a sbc to me. They were incredibly ugly cars and few were built.
If I am wrong I stand corrected. The word efficiency wasn't used-that is correct. But isn't it a factor in making this kind of decision? Power loss through any power transmission device is an important consideration in ultimate performance. I've torn apart Toronados from 66 through the early 70's. All the final drives look about the same to me. As far as "bevel gears" I mentioned, I think the correct term is hypoid but it is a distinction that doesn't matter. If you will look in power transmission books you will see that the power loss through chains and hypoid gears is very high. The point I was trying to make is that if you eliminate the hypoid gears, and chain and replace them with helical gears (aka modern fwd trans) you will get a larger fraction of the input power out of the other end. No one would deny that the torque handling capacity of the 425 is enormous, but it is also very heavy. I submit the reason that the chain was used in the 425 trans is that the basic 400 was modified to make the 425. In a low production car like the eldurado/toranado this was done to save design cost. I wish I'd known the final drives were scarce. About a year ago I cleaned out and sent about a dozen to the scrapper. I've got to get back to work now. I enjoy these exchanges and I think we all learn from them. Have a good day!
Larry

Cardealer, you have to clean out your mailbox, my email with pics keeps getting sent back because it says you mailbox is full.

its not full, not sure why i cant the pics unless you have the wrong email address:
tonypaul@fastestcar.com
thanks

I really didn't give efficency a consideration when I chose to build a Lambo with a THM325 & LT1. There were three driving reasons:

1. The swap is fairly inexpensive and is openended when choosing an engine.

2. The trans & drive train (axles, bearings, etc) are nice & big & able to take the shock of a little hotrodding. I'd hate to build the same car and then go out one night and leave the innards of a 125 trans all over some intersection.

3. My wife (whom I'm building the car for) wanted an automatic trans. Once again, this is a well proven trans for the sedate daily driver, and as such it should yield years of trouble free service.

BTW, that big chain drive = reliability to me.

Chain drives can't be that bad or GM would have abandoned them by now. All of GM's modern FWD automatics use chain drives.

opm2000,
That's a nice piece of work. Be interested to see more as it progresses. Built a similar machine several years ago. You have a lot of work ahead of you. Have you found headers for it? I had to make a set from scratch. Have you shortened the axles? I found I had a terrible bump steer problem. Had to go back to the dawing board for a lot more work. Anyway good luck.
Larry

Cardealer...sent em again...if you dont get it this time perhaps you can send me another email address

Larry,
The axels I'm using are stock Caddy axles that went with the 325 trans. Turns out they are just the right length, so no fabricating is needed, so far. These axles have a bigger diameter & bigger spline pattern than stock Fiero, so I'm using Cieria Knuckle & bearing. Knuckle looks just like the Fiero knuckle, just has a biggger bore for the bigger bearing. Everything lines up fine so far.

I'm building using the Joe Wynman CD "Guidelines" and his aproach to bumpsteer is to fabricate something very similar to what RCC sells. There is a thread currently discussing the merits of this method. I'm able to at least equal the stock bumpsteer using Joe's setup, if not actually eliminate some of it. Won't know till I hit the alignment shop, cause my bumpsteer measurement tools are very crude.

I'll see if I can dig up a few pics.

One alternative that is very tempting, but leads down the path of "more time spent fiddling around" is to fabricate a simple connector that attaches to the top of the knuckle, where the strut now attaches, which would allow connection of an upper controll arm. Then a new set of lower & upper controll arms is made for the rear. This would be very adaptable to the tube frame I've made. A fellow Diablo builder engineered this setup.

For now, since I'm not building an autocrosser--just a daily driver, if I can achieve something close to stock bumpsteer, I'll be happy.

Hey Tony_C...

could you send me those pics also?

I'm lookin in to doin that cadyy 500 conversion and I wanted to see all that it entails and I was curious about flipping the dif... emails d_ri2k4@earthlink.net

but i was gonna do a normal transverse V8 SBC but, with the advice of others, the fiero tranny's just can't withstand a lot of torque, and the caddy 500 with that TH-425 trans I can build a lot of power and not worry about spending tons of $$$ beefing up and fixing the th125 initially and every time it breaks...

quote Originally posted by montesa311: RedHaze86SD4--- tell me if im rong, but isn't a rat a big block?? And a small block is a mighty mouse?? Anyhow, i dont think i would want my nutts in a vice, i think i will pass on the offer. on another note, about what are the figures for making the fiero stand on end, that might be kinda cool to have one that does, but it sounds like doing a small block will be wayyyyyyyyy easier. What kinda power would i have to make to have one do it?

It's not so much about power as it is about killer traction and a killer tranny. You'll need a transbrake with an auto and GREAT slicks. The fiero should be pretty easy to wheelie though. How much are you looking for? Front tires off the ground or the rear end on the ground? I really can't say for sure but I think if you only have around 450ft/lbs with the above mentioned items you should get a good one.

D-Ri2k4
u have email.

bump

Hey, Matt Kneen is standing right next to me and his 500ci Fiero has cleaned the clocks off of many a nitrous powered beast let alone ANY other Fiero's, Any one want their clocks cleaned by 500ci of Fiero power just show up at Porkies in St. Paul on any given Friday this summer. I've personally seen this beast run, It's impressive. ps, Many testaments available,including;2001 Firebird formula,2000 Camaro SS's,Corvette Z06's,nitrous powered '67 Firebird, etc.(oh and to those who said it couldn't be done,HA)(pictures coutesy of minnesota green,earlier in this session)

quote Originally posted by Porsche928DRP: Hey, Matt Kneen is standing right next to me and his 500ci Fiero has cleaned the clocks off of many a nitrous powered beast let alone ANY other Fiero's, Any one want their clocks cleaned by 500ci of Fiero power just show up at Porkies in St. Paul on any given Friday this summer. I've personally seen this beast run, It's impressive. ps, Many testaments available,including;2001 Firebird formula,2000 Camaro SS's,Corvette Z06's,nitrous powered '67 Firebird, etc.(oh and to those who said it couldn't be done,HA)(pictures coutesy of minnesota green,earlier in this session)

AMEN!!!!!!!!!!!!!!
i have found my new best friend!!!!!

Anyone tried a 514 bracket motor yet?

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--Jess--

If you expect the unexpected, was it really even UNexpected in the first place?

'85 SE, 4cyl, 5spd, silver/grey

'02 Yamaha R6, blue/white, 3200 miles, LIGHT case of roadrash

'02 for sale/trade for Fiero(s)

i have been reading up on this, and i think that the small block chevy is definatly the way to go. What are some recomendations for building, or recomendation on plans for a small block. I have been tring to think of somthing that maby dosent have a huge torque curve right off the statr, so i dont kill tires, but maby not. pass on the info

Porsche928DRP-

Do you have any more pictures of that fiero or do you know what times this guy is runnin in the 1/4 ??

Do you know of any way I could get in contact with this guy? I am going to do this conversion and I haven't been able to find much info other than what i've gotten from Cardealer and Tony_C

-DRye

quote Originally posted by cardealer: AMEN!!!!!!!!!!!!!! i have found my new best friend!!!!!

quote Originally posted by D-Ri2k4: Porsche928DRP- Do you have any more pictures of that fiero or do you know what times this guy is runnin in the 1/4 ?? Do you know of any way I could get in contact with this guy? I am going to do this conversion and I haven't been able to find much info other than what i've gotten from Cardealer and Tony_C -DRye

Rockcrawl has a webpage with all the info needed to do a th425 swap if you want to go without reversing the differential. Otherwise you're in the same situation as me, figuring it out as I go along because although people say they have seen it done no one has ever shown me proof.

YA... Rockcrawl's page is fieroaddiction.com right? Its not just the 425 conversion I wanted pics of and such but the caddy 500ci conversion...

-DRye

The hardest part of the conversion is the TH425, not the 500 ci Caddy engine or any other GM engine for that matter. any Buick, Olds or Pontiac engine will bolt to the TH425, any Chevy will bolt to it with a $50 adapter from TCI. The bulk of the work is getting the tranny to fit and mated up to the Fiero axles.

quote Originally posted by TONY_C: The hardest part of the conversion is the TH425, not the 500 ci Caddy engine or any other GM engine for that matter. any Buick, Olds or Pontiac engine will bolt to the TH425, any Chevy will bolt to it with a $50 adapter from TCI. The bulk of the work is getting the tranny to fit and mated up to the Fiero axles.

expect "some" problems with "some" gm engines other than olds and cadillac due to oil pan clearance. all engines other than toronado and eldorado will havee to have the oil pan cut and modified. on longer stroked engines there could be clearence and oiling problems by doing this. i was going to use a sbc 400 for my conversion engine but it looked like the pan was going to have to be cut in such a way the crank might hit the pan and/or have oiling concearns.
just some of my nightmares........

What kinda moding im i goning to have to do to that th425 to get every thing to hook up. For the time money and effort, is this conversion really worth the edffort?

quote Originally posted by montesa311: What kinda moding im i goning to have to do to that th425 to get every thing to hook up. For the time money and effort, is this conversion really worth the edffort?

First off you are gonna lose most of the trunk. If you are going to place the engine and tranny in the car with the engine facing forward you should check out rockcrawls web page, it is in another post on this subject. expect alot of cutting and welding. otherwise, it's not too difficult once you get the engine and tranny mounted. TCI sells an adapter plate to bolt a sbc to a bop tranny. you will have to fabricate some adapters to mate the th425's final drive to the Fiero axles.
If you're going to attempt the reverse rotation swap things get much more difficult. You will still lose most of the trunk although not quite as much. the main problem I am encountering is what has to be done to the final drive to rotate it. First you have to make an adapter plate to rotate it 180 degrees. It doesnt simply rotate because the bolt pattern is not symmetrical. also, if you have ever seen a TH425 final drive, you will know that the stub axles that come out of it are not equal lengths nor are they the same diameter. you have to fabricate an adapter to mate with the long stub axle that goes under the oil pan. then you need to fabricate a special nut plate which has to be installed on the side gear of the diff, this requires taking the unit apart and pressing it into the gear. Then the bulkhead which goes across the firewall below the rear windshield has to be modified, it has to be pushed back to make room for the back side of the tranny. You cannot use the mounting plate and motor mounts that come from the caddy because there is not enough room left over so you have to fabricate a mounting bracket that goes around the tranny and not behind it. I used standard th350 tranny mounts to install this bracket to the fabricated crossmember.
for the engine, you cannot use the 3 holes on each side that typically mount a sbc to the frame, one side is blocked by the tranny and the other side hols are needed to mount the bearing hangar which supports the long stub axle that goes under the oil pan. I used front engine mounts from a 55-57 chevy, these mount to the two holes on each side of the timing chain cover on the engine. all sbc's have these holes or at least the bosses for drilling your own. A company called danchuk sells the brackets. Right now I am working on mating that th425 axles to the Fieros, rotating the diff moves the distance between the axles making the need for shorter ones. thats where I am currently. I think the major stuff is out of the way, the rest is hooking up the hoses and accelerator cables and getting shift linkage to work, the stuff that will be a problem in any swap anyway.

Matt could build another 500ci beast in less than 1 month with a mild amount of work and $500.00 excluding car,engine ,and trans.When he pulls it out of winter storage there will be more pictures posted(maybe even wheelies!)He uses chevy lumina minivan springs, fabricates axles(fiero/cadillac axles),trans is not reversed,(engine faces forward),stock caddy gear ratio is perfectly matched with the small fiero wheels(24"-25" OD),stock radiator(no cooling issues),Matt Kneen fabricated exhaust,heat sheild was installed around exhaust and the gasket on the trunklid was removed for airflow(my contribution), handling is good w/aluminum control arm bushings in the rear (rear swaybar mandatory),everything looks stock from the exterior( no holes in trunk lid, everything under the hood,rear trunk was removed,stock appearance of the exhaust outlets),vertical cradle bolts have spacers to keep the engine under the hood, horizontal cradle bolts have aliminum bushings,and a Matt Kneen custom cradle. Hope this helps for now. PS. this is a daily driver in the summer.

As with most anything, there is more than one way to skin a cat.

Tonyc has described one way.

Another way is to use an LT1 engine, with Camaro acessory brackets.

Standard TDK triangular engine mount brackets allow bolting the engine up using the standard side-engine-mount bolts & locations.

By using two standard exhaust manifolds from the stock LT1 (two of either the left side or right side, I forget which)the exhaust is able to be routed without interferring with the AC, other accessories, or the trans.

Mounting the engine & trans to the cradle require simple fabrication, easily done in a few days with carefull measurements along the way.

By using a thm325 (not 425) you get a different differential & output axels. Stock Cadillac axels will bolt up to the outputs with no need for special adaptors.

All this fits into the Fiero by cutting into the trunk space. If you want to do the reverse rotation thing, I hope you are looking at a Countach or Diablo, which use a 5" or 11" chassis stretch. Stock Fiero will be a bit out of question, IMHO.

Reversing requires fabricating a "tunnel" and a transmission-type driveshaft which fits inside the tunnel. The tunnel goes where Tonyc described only an adaptor plate. The driveshaft connects the trans output shaft to the differential. Imagine two similar adaptor plates with a big pipe welded in between and you have the tunnel.

The differential is rotated 180deg and slid back from the trans output shaft 5" to 10" by my measurements. This is the length the tunnel is made to fit. The output axels are retained with "c" clips, just like the Fiero axels, and these output axels are swaped side for side. Once again, the sotck Cadillac axels are used from there out.

I will say that while I have done all the work to put an LT1/325 into a Diablo I'm building, I have not done the reverse rotation work. I do have everything in place where I have been able to take measurements and do tentative placing & jigging to test these theories, and I think it would all fit.

do you have any pic??? that might help a ton

Montessa,
If you will look about 1/2 way to the top of this page, you will see my LT1/325 w/caddy axles in "normal" or pulleys to the front orientation. Although it is mounted in a tube chassis, the cradle/engine/drivetrain will fit right into a standard Fiero engine compartment. You just have to chop out a bit of the trunk.

I have no pics of the reverse solution because, as stated above, I haven't done it. I wanted to do it when I started this Diablo. I had heard of it being done, but found absolutely no credible accounts, pictures, how-to's, or examples. The one vendor who supposedly sold tube cradles for the swap told me they had never done one:>??
Once I had done this fabrication work, I figured out what I have described in the previous post.

Has anyone been able to keep a 325 trans together w/over 500 ft/lbs of torque and are there any shift kits to use with this project.(the chain is over twice as strong on the 425 and there is a shift kit available)

I spoke with three different transmission overhaulers, sounding them out about their experiences with this entire line of transmissions. Afterall, they have been around a good while, and they should have a track record.

All three shops said the same thing, independantly:

1.the THM425 was an absolute tank. There are versions with switchpitch, versions for motorhomes, and daily driver versions. It carries a weight penalty.

2.the THM325 has a smaller drive chain than the 425, but is well built, and can take "stoplight indys" all day long.

3.the thm325-4L has an overdrive gear for better mileage, but it has the weakest drive chain, and has the reputation for breaking down, as compared against the other two trans in the family. All shops thought GM went overboard on their streamlining of the case and innards. The overdrive will not hold up to repeated racing.