Hello all, my girlfriend has a POS 1986 corvette C4 sitting in her driveway with a doug nash 4+3 tranny, the overdrive doesn't work. Her mother can't find anyone to sell this to at a price of 2,000 dollars and I may consider pulling the L98 from it and having my cousin put it in my car which has a T-5.

What are some difficulties I will have when attempting this swap? Can I even use the doug nash 4+3 manual tranny from the corvette?

If not I know the T-5 Is too weak for the torque of the L98, but is it possible to strengthen the T-5?

Besides changing the plumbing around (TBI-TPI) what other things will I need to change? what kind of a harness would need to be used?

Any info on how to do this and what parts to invest in would be helpful. I am not much of a mechanic but my cousin is, he works in a high performance specialist shop. He has a 4th gen f body but he doesnt know much about the corvettes.

Any info on this would be much appreciated, I could probably acquire the engine and tranny for a good price from my girlfriend's mother, she really doesn't know what she has.

Thanks to all who respond in advance

Mikeye

 

The way to strengthen a T5 is spelled "T56". I'm not familiar with the tranny in the Vette, but I'd be surprised if it fits directly.

You'll need a TPI harness. I'm not completely sure, but I believe the Vette harness can be made to work.

I keep hearing the Vette oil pan and oil pump are different than f-body, but I couldn't vouch for that.

 

Any pics of the Corvette....?

 

It is true. The sump is closer to the middle on the Vette engine, not to the rear like the F-cars... you will need an oil pan and pump/pickup from an F-car.

 

The vette is in pretty restorable condition, no body damage just shot paint all around. The electronic overdrive on it is broken and the clutch shakes.

She is selling it for 2000 dollars, some of you will probably say just buy and restore the vette, but im already getting my f car painted, and overall I like it better than the vette. The vette is uncomfortable to sit in. You need to basically jump in and climb out of it.

Im trying to figure out if I buy the L98 for 800 dollars if it would be worth it to buy the oil pan and other components, or just buy an L98 out of another f car

I am also unfamiliar with the TPI parts I must purchase, I believe it will be different than the corvette... Or could I just take everything that sits in the corvette (besides the harness) and just drop it in? im doing my research, any input on the parts I need to buy would be appreciated! thanks all

mike

 

I'd buy and fix the vette personally as it will be much easier to sell in the future if you ever wanted to get rid of it, its up to you though, you could buy the whole car for 2k pull the engine and probably still sell the car for more than you paid for it if you wanted to go that route.. seems silly to part out a vette to fix a bird though.. is the engine actually in good enough condition to where this swap makes sense? How many miles on it? Is it the aluminum head version or iron? Both were available in 86 and depends on when the car was built. I've also heard this stuff about the vette having a different oil pan and such, never have been able to confirm it though, my 86 vette has the 350 from my old 89 rs in it with the same pan I had on my maro, no exhaust clearance issues or anything so that one always left me scratchin my head..
The vette accessories are different so you would want to retain your assessories. The TPI setup is the same, it would probably be easier to use an f-body harness though.

 

Since it last ran (about 5 years ago) it ran very strong, only 90k on the motor. It doesnt have any fluids in it and the battery is dead. It makes sense if you love your bird enough though, doesn't it?'

it has the aluminum heads btw (edit)

 

i just installed a 350 form a 84 cfi vette. the oil pan is a little different, but if fit without a hitch?

 

4+3 is a really weak trans with poorly designed bearing setup. You could get the beefy T5 from a mustang but the T56 is the better choice. As for my opinion.... vette is a better street car than the camaro but it all depends on what you want.

 

4+3=PROBLEMS

 

How long has it been without fluids???? Make sure it isn't seized..

 

My nephew had an '86 Vette several years ago. He got tired of the $500 per event repair bills, typically things the typical do-it-yourselfer couldn't handle (like AC going out every 3 months). He sold it, got a 3rd gen, was disappointed in the downgrade of ride, handling, and comfort, sold it. Just bought another less-modified 3rd gen.

Vette vs. 3rd gen? Mostly a matter of $'s.

 

I figured the vette is probably a better ride, im reconsidering possibly buying the car so I wouldnt have to deal with a swap of motor and tranny on my base firebird, id need to replace the rear end as well as suspension pieces to even make it close to vette quality handling.

I brought the idea up to one of my family members and hes like those C4s are crap they are white trash bleh bleh bleh.... I didnt think any vette was crappy. I think hes full of crap

 

The mid- to late-70's and 80's Vettes were certainly not "world class". An 80's Vette will out handle and have a better ride than a 60's Vette, but probably not out-run it. I'm still convinced that the real reason 3rd gen 350 f-bodies didn't get 5-speed trannies is because they would out-run same-year Vettes if they did, and the Vette has always had to be the fastest of the line.

I vaguely remember hearing what others are saying about the 4+3 tranny. I don't know what you could swap in its place, but I'm sure there's something. My nephew's '86 was auto.

We had a manager at work who had an '88 Vette new until he retired in the early 90's. He sold the Vette after he retired and ordered a C6. He also got tired of the little failures, the biggest complaint being having to replace the alternator annually.

There is no doubt that the C5 and C6 were big steps forward.

 

Well the reason I now consider keeping the vette is because there is much less i would need to modify performance wise, you know? I won't need to replace a rear end, i wont need to get a T56, i wont need to swap an engine... Although I like my firebird more I am just not sure if its practical yet. If I were to put a rebuilt 350 into my bird, I would no doubt breathe new life into it. My L03 is going on 142k miles and will probably not last me much longer... Although it is still a strong running motor.

Many people seem to hate on the TBI 305s but honestly its been a very dependable motor for me and what seems like a bunch of others as well

 

you're a step ahead of the same if the vette was origionally a manual tranny car as they normally came with the stronger d44 instead of the d36 auto cars typically came with. Still by no means bullet proof and not a great choice if your doing a lot of drag racing but they hold up decent on the street. The most common replacements for the trans are the zf6 and t-56. Info on the swaps should be easy to find over at http://forums.corvetteforum.com/zeromain It's a decent source for vette only info but no where near the same level of knowledge as TGO.

 

buy the vette you'll love it every time I ride in my friends c4 I want one

 

If C4s are so good where did these terrible reputations I keep hearing about them coming from? Them being the sub par vette... Why?

 

It's all in the perspective.

I've only ridden in one Vette in my entire life, and never driven one. That Vette was a '66 427 4-speed when I was 14 years old. It was noisy, rode rough, rattled, but man would it go! By today's standards, it would be considered sub-par.

The 2008 Grand Prix I'm driving for a rental car would out-run and out-handle some of the 50's Vettes (and probably some of the 80's as well), while getting better gas mileage.

Having to replace things regularly was just expected in 1966. It isn't acceptable now.

That's what it amounts to.