Help with motor swap

[Peregrine]

Hi, new to the forum.

I realize the topic of the 305 to 350 swap in a second gen has likely been covered before, but I can't manage to dig up much info on the swap or a write-up.

Basically, I have a 350 with an auto trans out of a 75' Camaro that I'd like to swap into my 81' T/A-currently with the 305.

What do I need?

Mounts?
Electronics?
Wiring?

Thanks for all and any help!

[kthxbai]

im stepping out of bounds here being a third generation owner, but i would say your mounts will be the same since its just another small block, you may want to upgrade them to poly. while the bay is empty.

the wiring depends mostly on what type of 350 you have, carb. or EFI

[96firephoenix]

out of a 75, no way thats EFI

[20-SS-00]

i did this swap with my 84 TA. there is nothing special needed for swap. just get a nice set of new motor mounts.

[Peregrine]

So the T/A electronics for the 305 will work with the 350? I can leave the wiring alone? The 350 is out of a parts car Camaro, I can just steal the mounts from it as well.

Both are carb motors with auto tranny. I'm not sure if they are the same tranny, but I'm hoping the tranny I already have in the T/A will work with the 350. Any thoughts on that?

Thanks!

[freebird67]

The tranny should swap out. Since it is a 81 T/A it should be a chevy 350 instead of a pontiac. If it is a pontiac (never know if someone swapped it) you will need a bop bolt pattern tranny.
After rereading your original post I say it will work because the 305 is a chevy motor and the 350 is in the camaro so it should be the chevy also. Just as the 305 may not be the stock motor for the 81 T/A

[freebird67]

1981 engine ID's for the 305's were DHJ and DHZ

[kthxbai]

sorry didnt see it was out of a 75- in that case wiring should be simple. I definitely agree get some nice mounts while you can. You should get all the info about both transmissions and engines so that you can straighten things out and so people can help you

[Peregrine]

Thanks guys. Here's the info I have:

The 75' Camaro has a 350 Chev mated to the auto tranny.This is from the factory, no previous swap.

The 81' T/A has a 305 Chev and auto tranny from the factory as well.

Are the tranny's the same? If I take the Camaro's tranny as well, will it all bolt up to the driveshaft and whatnot? If the tranny's are indeed the same, I'd rather bolt the 350 to my T/A tranny.

[kthxbai]

i would imagine that the transmissions will have the same overall length and therefore require the same length driveshaft. If you can you can just measure them bellhousing to tail and check, if not i would look around for a place online to decode both cars VIN numbers and get details on exactly what transmissions you're dealing with. the transmission mount should be the same either way. i am 90 percent sure they will be dimensionally identical.

[20-SS-00]

the 350 will bolt right up to the stock trans which should be the 700r4 in your 81. like i said before just make sure to buy a nice new set of mounts for the 350. also something to keep in mind. if you build up the 350 with a lot of power the stock trans in your 81 if it is the 700r4 doesn't seem to handle much hp. i blew through two trans before i decided to swap to a turbo 350 trans.

[kthxbai]

Originally Posted by 20-SS-00 the stock trans in your 81 if it is the 700r4 doesn't seem to handle much hp.

700R4's will blow up pretty easily with alot of hp/torque- however, they can be built to handle 800+ hp, and race prep. build kits start as cheap as 500 bucks. I dont know what labor would be like to have a speed shop do it, but I guess this all depends on your motor anyhow.

[20-SS-00]

Originally Posted by kthxbai 700R4's will blow up pretty easily with alot of hp/torque- however, they can be built to handle 800+ hp, and race prep. build kits start as cheap as 500 bucks. I dont know what labor would be like to have a speed shop do it, but I guess this all depends on your motor anyhow.

its true but i'm not sure how many of us have the cash for that, it least i didn't . that's why i went with a diff trans all together.

[Peregrine]

Do you know which transmission was OE with the 75' 350 Camaro? Is it the 700r4 as well? If it's a better trans than the one I have in the 81', I might as well pull that too.

[SnIpEr]

This page should help you with that question:

Camaro Transmission Information & Restoration

[kthxbai]

how much do you know about the mileage/condition of each transmission? I would choose which one to go with based on how well they are shifting... If the one already on the new motor is in good condition, I might suggest you just leave it on there and drop it in with the motor from the top.


by the way- i believe both transmissions are TH350's which if i remember correctly were the immediate predecessors of the 700R4 so they are essentially the same

[Peregrine]

If I post up both VIN's tomorrow, would that help you help me?

My T/A had a tranny rebuild a few years ago. The car has less than 60,000miles on it. The Camaro on the other hand...let's just say the car has been well used. If the trannies are about the same, I might as well keep mine.

[kthxbai]

VINs would probably be a good thing to decode anyways, so you might as well. Its a quick way to make sure both transmissions are identical since we dont seem to have a resident 2nd gen expert.

as long as they are the same sounds like you should keep the one with the rebuild. No sense in downgrading your gearbox...

[supjim]

When I did the swap in my 73 it is drop hook and go, everything was bolt in no probs. Only issue I have was the tail shaft length, not a bad issue just a pain really. All wires are the same mounting points the same hey they are the same car other then outside apperance. Go with sturddy mount poly is great for the price. take pics when you do it and make a write up about it maybe it can be a sticky.

[Peregrine]

Well, today I paid for the motor and I'm getting the tranny as well. I'm going to do a bit more research to figure out which specific transmissions I have. If needed, I can also take out the Camaro's driveshaft and rear end. Do I take the Camaro's electronics or just the engine and stick with the T/A wiring and electronics? Will it make a difference?

Thanks!