Venom_1138

Probably a dumb question, but I'm looking at a V6 Firebird that has an automatic transmission that needs some work done, namely replacing seals and the linkage cable... Maybe a rebuild could be in order, but I won't know until I dive into it. Either way I'm going to have to put some money into the transmission before the car is drivable.

That being said, I may eventually choose to swap a V8 into the car, which I know will require a new transmission. My thinking is, I'd prefer a manual transmission either way. But if I'm going to possibly swap out the engine down the road, I obviously don't want to invest a lot by buying a transmission that will need to be replaced as well. Will any of the V8 transmissions link up to a V6 so that I can 'future proof' against whether or not I decide to swap engines? (basically buy once, cry once) I know some people may say that ideally I should probably just go with a V8, but those seem to be in short supply in my region, especially at my budget. This way I can at least enjoy the car until I either have the funds for an engine swap, decide to buy a V8 model down the road, or build up the V6 and keep enjoying it mostly as it is.

I did try to use the search function, but every result I found was oriented toward swapping a V6 transmission as part of a V8 swap, but not so much about putting a V8 transmission into a V6. Either I worded it wrong or there's just not many people who have chosen to go the opposite direction on a transmission swap.

I'm leaning towards buying the car, but I just want to know what all my options are before I commit to anything. Thanks in advance!
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Drew

iTrader: (58)

You could just hand me the money you would otherwise pay for the Firebird, I'll shoot you in the foot, and we can part ways...

You would need a 6cyl transmission. Different bellhousings, different transmissions. Can it be done? Sure. Is there any reason to do it in this scenario? No, because it'd cost more than getting a used V6 trans and throwing it away when you're done with it.

It's still not really economically viable to V8 swap a V6 thirdgen. It costs too much to do it right than a person will save by starting with a V6.

Venom_1138

I was pretty sure it wasn't viable, but you never know until you ask. I've read you can link a V8 to a V6 manual, aside from the fact that the engine will chew the transmission up in short order. I was just wondering if the reverse was possible, especially since a V6 is highly unlikely to ever put out enough power and torque to thrash a V8 transmission.

I'm not 100% that I'd even do the swap, a buddy has a rebuilt 305 he was going to use on a project, but found a 350 he decided to to use instead. I mentioned the car to him and he planted the idea in my head and offered to sell me the engine for what he paid for it. I've read up on the topic, and I know there's a lot of work and parts that need to be changed out to do it properly. It was more me thinking, 'Well, if I buy this, I could maybe do that.' While I'd love a Trans Am, any 3rd generation Firebird to wrench on and enjoy would be fulfilling. I just like to keep my opinions open

Drew

iTrader: (58)

Assuming you're working with a manual transmission with a separate bellhousing, theoretically you can change the bellhousing to fit another engine. But then you have to find a clutch that matches the engine's flywheel/pressure plate, and the input splines on the transmission. Once it's all physically together, you have the issue of gear ratios being completely mismatched. Generally with a V6, you'll have numerically higher gear ratios to make up for the lack of torque. So with a V6 trans behind a V8, you're putting higher stress into the trans and the engine will be higher in the RPM than it would be with a more appropriate trans. Usually it's enough of a mismatch that first gear turns into a granny gear, and you're shifting to 2nd before you get out of the crosswalk or half way across the intersection. Going the other way, the V6 with a V8 trans, will be terribly sluggish. Like starting in 2nd gear when you're in 1st gear sluggish.

With an auto, you've got the added issue that the transmission isn't calibrated for an engine other than it's designed for. So like the above mismatch, but more complicated yet because you can't change the bellhousing, so now you have to get an adapter to bolt between the engine and trans...

It's just really not worth messing with. I haven't tried lately, but I'd expect a person could probably find an OK V6 trans on Craigslist, Facebook, whatever, because someone will have one laying around from their attempt at a V8 swap. I threw out a V6 700R4 a couple of years ago because it was in my way, and the engine was locked up, sure didn't ever see needing it. Few years further back I sold a V6 T5 with everything for $200 or something like that, just to get it out of the way. Should still be easy to find a deal on one, because no one wants them.

3.4 grape

iTrader: (1)

What year and what engine do you have? This could possible help.

OrangeBird

iTrader: (1)

Yep , the only way it makes financial sense is if someone has , for instance , a totaled 8 cyl 5 speed that was in good shape before the crash , and then buys a not rusty V6 car as a body swap . To one by each buy the parts for a V8 swap would cost more than just finding a "native" v8 car

Six_Shooter

iTrader: (2)

I do agree with the above, that it would generally be more feasible to just get a V6 trans, and if you do go through with the V8 swap, just replace the transmission at that time.

However, I will also point out that there is an off the shelf adapter available to mate a 60 degree V6 to a V8 trans. I will be using one in one of my projects, because the trans I will start with is an electronic trans and would take more effort than it's worth, IMO, to make a proper V6 trans work in it's place. My ultimate goal is to use a stronger trans that doesn't have a 60 degree V6 option, so this would mean that I will already have the adapter.

Sierra6

If you got your hands on this adapter, what else would you need for a T56 to work? Assuming the car was already manual. A regular flywheel and clutch for a T56 f body car? anything special you'd need to consider?

Galaxie500XL

iTrader: (1)

If you’re going to a T56 later, absolutely NOTHING can be reused, except the pedals. Bellhousing, flywheel, hydraulics, are all unique to the T56. Even the clutch is unique...it’s a pull type pressure plate.

Six_Shooter

iTrader: (2)

A lot of custom engineering and parts would be needed.

The adapter is for automatic transmissions and would not be suitable for manual transmissions.

Just off the top of my head, a custom flywheel would be needed, along with a custom pilot bushing, a custom starter or mount would also be needed due to the diameter of the flywheel.

This would be a lot of expense and effort, for a temporary solution.