need some help figuring out what engine

[lvngded]

Hey all,
I was thinking about dropping a Poncho 350 in my 85 GP project. I don't know what trans is in the car or if it will mate up to the Poncho. I can tell you from what I read here, I have an "H" vin and I have no overdrive, so a 200-r4 is not in my car. Any advice on what I may be looking at here. The current Chebby 305 and trans run fine, so I'm not in a rush do to this, but a buddy of mine wants the engine and is willing to buy me the engine I want to transplant to get it. Thanks all in advance.

Mike

 

[Volumeshooter]

If you have a chevy 305 mated to the trans now it is not likely going to be useful with the Pontiac engine as you would need a BOP bellhousing and the one you have will have the chevy bellhousing.

 

[lvngded]

Well, that's just crap-tastic. I kinda guessed that but was hoping that I missed some magical mystery post that told us to use it and it would be fine. LOL So I guess the next question would be what trans would I need to do this, and are there any gurus here who have done this and what else I would need to pull it off? Thanks again for the replys

 

[Volumeshooter]

It all depends on what your plans are for the car, cheap and easy(chevy) or complete build up(Pontiac). The easiest/least expensive thing to do would be to find a chevy 350 since your car is already set up for a chevy, just pull old one out and put new one in and you can reuse any accessories that you are not giving to friend. If you are gonna do the Pontiac swap 😀 you would need to find a trans with BOP bellhousing, a good TH350 or a 200r4 if you are looking for OD. If going with Poncho you will also need all the accesories, and have to change motor mounts and I'm sure a bunch of other stuff as well. I know Gbody_vet is in process of swapping out a Chevy 305 for a Pontiac 455 in his 78 GP so he should be able to shine more light on what all is really needed, you should check out his thread if you choose to go that way. Hope this helps and goodluck.

 

[Bar50]

Just find a big tank Bonneville and snag motor, trans, and brackets.
I did it a long time ago:

6x headed 400 Pontiac with Turbo 400. Some three tube headers and a shift kit. Added 3.42 gears form an S10. Ran like a scalded dog.

Sorry, those are the only pics I have of it, she went away a while back. It still gets tortured pretty regularly.

 

[dave1978]

You should be able to find a bell housing adapter from a Chevy trans to Pontiac engine for a decent price.

 

[lvngded]

I have a line on a parts car with a 3.8 in it. That should have a trans I can use, correct?

 

[rustyroger]

I have a line on a parts car with a 3.8 in it. That should have a trans I can use, correct?

Not if it's a th200. It wont live long behind any engine with much more torque.
If the donor trans is a 200r4 it will need upgrading as well.

Roger.

 

[Bar50]

Look,
I am a low buck kinda' guy. So, if you want to daily drive the car, how far do you want/need to drive it? If it is going to be a weekend warrior/cruiser/nice day or because you want to...
The '85 GP should have the frame tabs to accept a 200R4 overdrive trans, or use an aftermarket crossmember for dual exhaust(I consider it a must and the price to play with the last of the real GM rear drive cars). If its going to be a daily drive with some long hauls and freeway time, find a 200R4. Thats going to require a good transmission guy to put in a good shift kit/reprogram the valve body, governor, and servo(if you can read & follow the instructions, you could probably do it yourself).

Weekend warrior, I would look for a BOP Turbo 350/400 or whatever comes with the motor you find. I daily drive my Malibu with a SBC/TH350 I don't have any issues (well, the Q-jet is sorta' cold natured on frosty mornings). I don't have a street/strip gear in it though. My BBC/4-speed El Camino gets driven ALOT, it would be more, but, I need to put the headers on and have the exhaust fixed. It has a 3.42 gear, its not bad, I mean, with the 2.73 gear it had it would do 70 MPH just off idle.

So, decide 200R4 or Turbo350 or 400. Overdrive lets you get away with a rear end gear ratio thats WAY funner. But, street cars with 3.23-3.42-3.73 gears are so quick/peppy/salty without any other changes. The 200R4 also needs the correct kick-down/throttle pressure linkage/cable brackets in use.

I am also sorta' weird, in that I dig an Olds having an Olds motor, your Poncho having a Pontiac and so on... To me you score car guy points for it. Its a tougher road, but, pretty cool. Look at the responses on this board for a guys putting a Buick 350 into Regals, nobody does that....sure the easy/cheap way out is SBC, but, almost everybody has one, been there done that.

The easiest way to do the swap is to have the surgeon out look, your car needs a heart, you need a donor car. The cool things about donor cars, they offer all the other organs too, radiator, hoses, transmission and lines, belts, pulleys, brackets....etc. etc. etc. Even motor mounts. The donor pool includes wrecks, old big gas guzzlin' grandma cars, project cars, tow in yard auction cars, storage lot auctions, and dead cars in driveways and yards, long forgotten for smaller, newer cars....look for Bonnevilles, old big body Gran Prix, Grandville, Trans Am/Firebirds. Pontiac was none to stingy with 400's, they put them in everything. I know, we all want a 455, but, I'll take a running Bonnie' with a 400/400 anyday!

 

[dave1978]

Some 3.8 v6 had turbo 350transmissions and some did not. There is a good chance of finding on a late seventies 3.8 than ones from later years. I'm just remembering back 20 years ago when these cars were falling from trees with bad v6 motors and we were replacing then with older v8's.