sold my small block chevy last week and now i am in the process of building a 400 pontiac with a edelbrock torquer set up!!!. I just purchased a th425 this weekend. I know people have used the 455 pontiac but I cant find any information on it. Did a search and nothing came back. Anyone know of a link for a pontiac v8 swap with a th425??

longitudinal.... phase 1

That's SOOOOOO KEWL!!!!

That monster motor as got torque out the A$$ I've never seen a 400 or my pref a 455 in a Fiero, but I sure would like to. Talk about GRUNT! Keep us informed dude.

Phil

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87 FIERO GT 2.8 5spd
0-60 in 6.8 seconds!
If you found my advice helpful, please take the time to give me a positive rating. Thanks

righ around the time i first joined this forum i picked up a mag with a 455 fiero in it. search in general archives about the beginning of 2001 (can you search by date?). i think a couple of threads popped up about it.

A fellow that used to be in FOCOSEVA (my "home" club) drag races a 455c.i. using the TH325 transaxle ... and not in reverse rotation. Wheelies are a breeze to him. His first name is Dave & he lives in Ferncliff, VA. Those who attended the nationals in Williamsburg a couple years ago will recall his purple car.

are you in the market for a tri-power from a 70 GTO been rebuilt about 2 years ago but just built a wild 455 for the goat and we need more cfms . i have to see picture when done ,you will get a lot of looks when you get on it . pontaic 400 and 455 are toque monsters

quote Originally posted by breakneck88: sold my small block chevy last week and now i am in the process of building a 400 pontiac with a edelbrock torquer set up!!!. I just purchased a th425 this weekend. I know people have used the 455 pontiac but I cant find any information on it. Did a search and nothing came back. Anyone know of a link for a pontiac v8 swap with a th425??

Of course i would like a tri power but they arent cheap. Also the guy i was supposed to be buying the 400 from showed it to me and it is in peices and looks like it was burried at one time. but i am going to find another. I would like a 455 but the 400 spins up there quicker and thats what i am looikng for. Not much need for torque in a fiero. Thanx for the info on the swap guys.

Yes, the 400 (and other small journal engines) spin up faster than the 455, but don't forget that the Pontiac V8 is not a hi rpm motor. It's strength is torque and mid-range. Even the highest performance Pontiac V8's of the day had redlines around 6000rpm. If you want to buzz the motor faster, you may be better off going with a Small Block Chevy.

you would be much better off going with a cadillac eldorado 500 or a oldsmobile toronado 455. too many problems with oilpan clearence, starter(?), c/v axle output shaft brackets and a host of other issues that i cant think of right now. do your homework before you get in too deep.
good luck!

I have a buddy who owned a 400 some years ago.

He always told me that there was problems with the heads overheating.

If I recall correctly, the oil delivery to the heads was not sufficient.

Maybe somebody out there knows about this. Anyway, he told me if I was going to hotrod a 400+ to stay away from the 400 and go to another motor. I hope this helps, especially if you are just at the looking stage.

Just pick up an issue of High Performance Pontiac or Pontiac Enthusiast. There are many good Pontiac suppliers in there. Over heating on heads? What was the guy smoking? There are today many fast!!!!!!!!! Ponitacs out there. I personaly would look for a smaller in size engine. When I had my Trans Ams I was putting a 69 400 engine in from a Grand Prix LJ, same motor as the GTO base engine. I like the 400. Makes for a good engine. Lots of low buck mods can be done on the engine. Do yourself a favor and get one of the magazines!

[This message has been edited by solotwo (edited 11-04-2003).]

Don't listen to the naysayers. I used to race a Pontiac Trans am (79) which had a Pontiac 400 in it. It cost bucks to build, but when done, it will easily turn 7000 and put out 438 horsepower. Now mind you, this is with special length aluminum connecting rods, special pistons, tapered wristpins, titanium everything that could be, crossdrilled and lightened crank, and so on. Put close to $8000 in the motor though, it is NOT cheap to build, but it can be done. And there is no problems with getting oil to the heads(where do these stories come from).

I love the idea of a big block Pontiac in the Fiero, but I gotta figure Cardealer knows what hes talking about.

Probably much easier to get a Toronado 455 setup and talk to the 442 guys about a buildup.

I am also looking into putting a real Pontiac motor in my little Pontiac. I plan to use the TH325-4L. I didn't start the swap yet because I am busy trying to get my new shop closed in before the attack of the snow flakes. I hope to pick up my tranny this month or next and get started though.

I have been doing a LOT of research, and I don't foresee any major problems. I will have to notch the oil pan (like any other longitudinal swap that doesn't use the original Eldo/Toronado motor). As for the starter, I hope to use the original Eldo/Toronado V8 starter. The mounts will be all custom so that's no big deal.

The biggest drawback I see are weight (Pontiac motors are HEAVY), and excessive (for a Fiero) low end torque. Our only recourse with the weight is aluminum heads, intake, and water pump. There is an aluminum block coming out but I shudder at the thought of the price. As for the torque, I am using a lowly, gutless, late seventies 350 to start - so I probably won't have much torque or hp First I'll wake this motor up (350hp?) with good heads, cam, induction, exhaust, etc., - then if I really like the car and want to build a better Poncho motor for it I may look into a destroked 455 for a more oversquare, rev happy, motor.

Final thoughts:
Why a Pontiac motor?

*The "trick" element of having a Pontiac-powered Pontiac.
*They look absolutely killer with the right intake setup - wide is better.
*They can make power - sure it costs a little more but the cost is balanced out a little by the "different" factor, if you're like me.

perk

The main problem I forsee is the starter when mated to the th425. It will be close and i might have to go to a modified mini starter. but i wont know until i get my motor out of the trailer its stored in(along with like 200 other pontiac v8s) and i will also need my tranny back after its inspected. The guy i am getting the motor from also has some nice 4 bolt 350 sbc,s and if the poncho 400 doesnt work i he will trade it back. I am still looking for axles.And i am debating the whole reverse setup and rotating the diff.I know the 400 pntiac isnt a high reving motor. Bet it does get to its redline faster than the 455. I am going with a 4x 2.11 head and I am shooting for some descent h.p. #s N/A at first than using a 301 turbu setup to give a little kick in the a&&. I wish i could find more info on the pontiac v8 swap but I cant find and details about it anywhere.

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'86 GT poly suspension.
Now back to the drawing board!!
Here is the new project.
400" Pontiac.8.7:1 Torquer set up. 4x heads matched and ported. 301ci turbo unit. all said and done i will be shooting for 475 to 500 h.p. Right now I am just in the rebuilding motor and tranny stages.

With a small (or big) block Chevy the starter is on the right (passenger) side of the block. The standard procedure is to simply notch the TH425/325/4-L bellhousing a little to clear the starter.

With the Pontiac motor this can't be done because the starter is on the left (driver's) side of the motor - that's where the transmission is with the Eldo/Toronado transaxle. The best solution I see is to use the Eldo/Toronado starter that was designed for this transaxle. It bolt directly to the bellhousing, as opposed to the bottom of the engine block.

perk

[This message has been edited by perkidelic (edited 11-05-2003).]

quote Originally posted by cccharlie: I love the idea of a big block Pontiac in the Fiero, ....

Pontiac only had one size block.

Roy

quote Originally posted by breakneck88: The main problem I forsee is the starter when mated to the th425. It will be close and i might have to go to a modified mini starter. but i wont know until i get my motor out of the trailer its stored in(along with like 200 other pontiac v8s) and i will also need my tranny back after its inspected. The guy i am getting the motor from also has some nice 4 bolt 350 sbc,s and if the poncho 400 doesnt work i he will trade it back. I am still looking for axles.And i am debating the whole reverse setup and rotating the diff.I know the 400 pntiac isnt a high reving motor. Bet it does get to its redline faster than the 455. I am going with a 4x 2.11 head and I am shooting for some descent h.p. #s N/A at first than using a 301 turbu setup to give a little kick in the a&&. I wish i could find more info on the pontiac v8 swap but I cant find and details about it anywhere.

yes the starter wil be a big problem, im not sure about the tooth count, pontiac flexplate to and cadillac/oldsmobile starter.
the greatest problem i see is your oil pan clearance. to get enough notching out of the oil pan for the output shaft to go through the oilpan the bottom of the rods will be hitting the bottom of the oilpan where you notched it out. there is not a main cap right there. oiling maybe a problem since i think the starter is now going to be were the oil filter sits. a non reverse rotation setup will definatly make the car very unstable and unsafe unless you use something like helds old longitunial setup. although you see pretty good power improvements with the setup you are planing, but you will be loosing a great deal of the balance of the car. plus with all the power you are planning on having it really wont be all that effective without something better than the 3.07 final drive gear ratio. i.e. you still run the risk of getting beat by some punka$$ kid in a rustang.
if you plan on doing the reverse rotaion setup, well you still have many of the same problems with the pontiac engine, but you can retain some of the cars balance. if you do a reversing set-up, i am currently redesgining my reverse rotation setup to something completely better. i should be done with a finished working unit in about 2 more months.
good luck!

What is really needed here is to find the person (people?) who have done this and find out how they did it, and what it took. That is the best way to find out whether the end justifies the means. The one thing that I heard that sticks in my head is that someone out there has done this swap - and it worked. I'm gonna step up my efforts to find info.

perk

quote Originally posted by cardealer: i am currently redesgining my reverse rotation setup to something completely better good luck!

Well, your first reversed version certianly showed some original thinking, so I can't wait to see what the deal is.

I did a "dry fit mockup" reversal by flipping the diff and extending it away from the trans by a few inches. A simple tunnel is fabricated to connect the trans & diff, and a short trans coupler is used to connect the trans output shaft & diff input splined hole. There are several speed shops that can fabricate the coupler shaft out of off the shelf parts, for a very modest price.

quote Originally posted by mrfixit58: Pontiac only had one size block. Roy

Yes, big

Hey thats going to be a kick ass build up, plz try to do a how to on this project im one of those that for a future mod is going for the 455ci pontiac engine so a tutuorial on this would be nice , good luck.

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mod it until is perfect.

http://members.cardomain.com/boricuaso

If I can find hard parts to rebuild my 425 trans. I need a gov'nor adn a pump.

quote Originally posted by breakneck88: If I can find hard parts to rebuild my 425 trans. I need a gov'nor adn a pump.

should be the same as a th400.

quote Originally posted by cardealer: the greatest problem i see is your oil pan clearance. to get enough notching out of the oil pan for the output shaft to go through the oilpan the bottom of the rods will be hitting the bottom of the oilpan where you notched it out. there is not a main cap right there.

cardealer, it sounds like you have tried to mate a Pontiac motor to the TH425 before - is that correct? Just a few quick questions:

If that is what you did, doesn't the TH425 have bigger axles than the TH325-4L?

If so, do you think I would be able to clear with the smaller axles?

When you reverse by flipping the diff, does it push the intermediate shaft closer to the crank or farther away?

What is the reason you decided to not flip your diff?

Thanks in advance,

perk

Breakneck88,
You might want to look here for 425 parts:
http://www.aceomatic.com/catalog/automatics/series.asp?t=19

or here for 325 parts:
http://www.aceomatic.com/catalog/automatics/series.asp?t=18

or here for a nice 325 diagram:
http://www.aceomatic.com/catalog/automatics/illustration.asp?t=18

Thats exactly what i was looking for! OPM you rule!!!!!!!!!!!!! Oh yeah I just found a good deal on an entire cadillac 500/425 set up with exles (70,000) $500!!!!!! How many motors can i put in a GT?

quote Originally posted by perkidelic: cardealer, it sounds like you have tried to mate a Pontiac motor to the TH425 before - is that correct? Just a few quick questions: If that is what you did, doesn't the TH425 have bigger axles than the TH325-4L? If so, do you think I would be able to clear with the smaller axles? When you reverse by flipping the diff, does it push the intermediate shaft closer to the crank or farther away? What is the reason you decided to not flip your diff? Thanks in advance, perk

never tried actually to bolt it together, but i did measure it all out back when i was researching on doing a longitudinal set-up.
the axle is different in the mounting flange and in diameter, but its the output shaft that goes through the oilpan and bolts to the block. and yes the th325 and th425 (th425bigger) are different sizes. even though the th325 is smaller i dont think its anywhere near small enough for the clearence needed. you dont only need clearence for the output shafts but also for flex or stretch or what ever you want to call it when the rotating mass of the output shaft starts to spin via some major torque.

im not sure about anything when it comes to flipping the final drive over you need to address that to TONY_C. hes a great guy and in my book hes the king of flipping final drives!!!!

flipping the final drive is not some easy task. i had kinda heard how tonyc was planning to his, i just felt i would like to try to build somethng dfferenrt no one ever has.

Yes, I am in the process of doing a reverse rotation swap with the diff flipped. First off, I have seen Pontiacs mated to th425's so I think you can get around the clearance issue between the main caps and the intermediate shaft from the diff. You may have another problem though if you use the pontiac engine with the diff flipped. Rotating the diff 180 degrees places the engine a bit further off the center of the car than when the diff is in its normal position. If you look at a eldo, you will see the engine is offset slightly (to the pass side) about 3" i think. this is so the diff has room in the chassis and the axles are the same length. Flipping the diff necessitates moving the engine further over, in the case of the Fiero, over more to the driver side. With a small block chevy I barely have enough room, with a pontiac i think you might be hitting the strut towers, especially if it's an '88, where the strut towers are closer together than other years. Flipping the diff requires you to make an adapter plate to correct the bolt pattern on the diff because it is not symetrical. With my engine and trans in the car (on an 88 cradle, the axle flange centerlines of the th425 sit 4" above the cradle, the bottom of the flange is about 1" from the top of the cradle. Hope this helps. I have some pics if you want, send me an email and i will send them to you.

[This message has been edited by TONY_C (edited 11-07-2003).]

Thanks guys. I hope that this information will benefit others besides myself. I didn't mean to hijack your thread breakneck88, I just figured since it is about longitudinally putting a Poncho motor in a Fiero we could keep some of the info together.

Thanks for the info and the tip cardealer.

Hey Tony C! How ya been and how's that "tude" coming along? I still have all those great pics you sent before. I just got a little shaky with the thought that my plan might have had a major flaw! Fabricating my way around minor obstacles is fine, but the intermediate shaft being smacked by the crank or rods was more than I wanted to deal with.

That's good information about the offset (sideways). I noticed the slight offset that the transaxle naturally requires, but didn't realize that it increases with a flipped diff.

Soon, soon, soon I will have this shop closed in and be able to start wrenching, fabricating, and welding. Can't wait to have some actual longitudinal swap experiences to share in these threads! It's really something how we can all be doing something so similar, but they're all unique.

perk

Now way!!! Not hijacking at all! At this stage every bit of info is indespensable!! I really appreciate others input and now i have more info than i could have thought of asking for!!!! You guys are O.K. with me!!

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'86 GT poly suspension.
Now back to the drawing board!!
WHO KNOWS WHAT THE HELL I AM GOING TO STICK IN THIS CAR????? I SURE DONT!!!

tony, Could you post some of your axle pics here. I am sure there are a few people who can benefit from them...

quote Originally posted by breakneck88: tony, Could you post some of your axle pics here. I am sure there are a few people who can benefit from them...

Scroll to the top of this page, second post. click that link and go to page 4. My axles are on that page. You will also see that the diff is flipped.

Tony, you are a sick sick man!!!!! I guess with all of the measuring i have done there really isnt any other way than to just pick up a poncho motor, th425 and a cradle and have at it.

And for any of you other people interested in going longitudinal, too ...

I have a rebuilt TH425 with differential and axle shafts for sale. If interested, send a PM with your e-mail address, and I'll reply with pix. With a $500 purchase price, I will haul this thing within a 250 mile radius from Yorktown, VA. ... or about as far as Hagerstown, MD.

I have said it before, that is a real good price!!!!! I wish i would have known about it before i started this tranny thing!!!! Mine is in the shop being rebuilt now. I still have to find a stall!!! I am going to do the 400 pontiac thing... hopefully it will all work out!

Breakneck...just curious...what are you paying to have your TH425 rebuilt?

quote Originally posted by Arns85GT: I have a buddy who owned a 400 some years ago. He always told me that there was problems with the heads overheating. If I recall correctly, the oil delivery to the heads was not sufficient. Maybe somebody out there knows about this. Anyway, he told me if I was going to hotrod a 400+ to stay away from the 400 and go to another motor. I hope this helps, especially if you are just at the looking stage.

A 400 what? The Pontiac 400 was one of it's best performing engines, ever. Sounds like your friend had a 400 Chevy, which did have overheating problems if you weren't careful. It used "steam holes" for coolant in the head due to the larger bore. Two totally different animals.