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Considering new engine/tranny for 1981

 
Old 02-14-2019, 08:31 AM
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foundvettelifeisgood
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Default Considering new engine/tranny for 1981

I have a nice Navy Blue 1981 coupe. It's an honest car that runs and drives like a 1981 corvette. Having had a C5, a C6 and a 2017 Camaro 2SS, the 190hp stock 1981 motor and long throw stock 4sp gear box is just underwhelming. I'm contemplating a crate motor and 5 speed Tremec. Who has done this conversion? Has anyone paid to have it done? I'm wondering what I should expect in labor.

I could sell the car and move on to modern performance, but I'm a sucker for the 80-82 body style. Please chime in with your thoughts.
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Old 02-14-2019, 12:28 PM
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Douglas Mariani
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I've done a few back in the day. Parts (8-10k) and labor (5-7+ k) will cost you more than the car is worth.
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Old 02-14-2019, 03:15 PM
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Big2Bird
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There is a member here that bought a whole new modern chasis and ls conversion. $25k I think.
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Old 02-14-2019, 03:27 PM
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Originally Posted by foundvettelifeisgood View Post
Who has done this conversion? Has anyone paid to have it done? I'm wondering what I should expect in labor.
:
Tons of people have done what you are describing. There is a very large difference in cost between doing it yourself and paying a shop to do it. If you pumped up your current engine yourself to 300-350 hp via good used heads and camshaft then found a junkyard Camaro t5 to put in with your own fabrication you could probably get away with a budget of $2000-3000. Having a shop do everything with a new crate SBC and a new tremec trans kit could be $15-20k.

.02
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Old 02-14-2019, 05:53 PM
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Also, the trans itself is fine as long as you dont need overdrive for highway trips. A good Hurst shifter will make the sensation of rowing go away. Then engine upgrade is much less doing.
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Old 02-14-2019, 07:47 PM
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drwet
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You may be able to fix the long throw on the gearbox for little or no cost. I had a '66 and the shift levers on the transmission had two holes in them. Converting to short throw was simply a matter of moving the shifter levers to the other hole in the shift lever. You have to readjust the shifter after but for a couple of hours work, you've got a short throw shifter. Not sure if your '81 offers the same option. My '79 was born with an automatic so I'm not sure what the factory setup looks like.

As for the lacklustre performance, a 427 small block makes a big difference.
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Old 02-15-2019, 01:36 AM
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PeterC3
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Originally Posted by foundvettelifeisgood View Post
I have a nice Navy Blue 1981 coupe. It's an honest car that runs and drives like a 1981 corvette. Having had a C5, a C6 and a 2017 Camaro 2SS, the 190hp stock 1981 motor and long throw stock 4sp gear box is just underwhelming. I'm contemplating a crate motor and 5 speed Tremec. Who has done this conversion? Has anyone paid to have it done? I'm wondering what I should expect in labor.

I could sell the car and move on to modern performance, but I'm a sucker for the 80-82 body style. Please chime in with your thoughts.
What do you mean by a crate engine?
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Old 02-15-2019, 07:06 AM
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Originally Posted by PeterC3 View Post
What do you mean by a crate engine?
A term that is being overused these days that means buying a complete engine and having it shipped in a crate as opposed to getting your engine rebuilt locally.
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Old 02-15-2019, 10:29 AM
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Originally Posted by PeterC3 View Post
What do you mean by a crate engine?

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Old 02-15-2019, 02:50 PM
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PeterC3
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Yeah.... this is the crate my GM 383 stroker came in.
Never do that again.
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Old 02-16-2019, 02:31 PM
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Originally Posted by PeterC3 View Post


Yeah.... this is the crate my GM 383 stroker came in.
Never do that again.

Peter, this is what I meant by crate engine. What was the nature of your bad experience?
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Old 02-16-2019, 02:42 PM
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PeterC3
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Here's the link to the thread:
https://www.corvetteforum.com/forums...ine-blues.html

I wouldn't buy another GM crate, quality isn't there in my experience. Chinese parts assembled in Mexico. Had to redo the valve train after slighting upping the cam.
I went the crate route for simplicity, if I could turn back the hands of time I'd have a custom engine built, it would have been cheaper and better all at the same time.

Good luck!
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Old 02-16-2019, 03:13 PM
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Originally Posted by PeterC3 View Post
Here's the link to the thread:
https://www.corvetteforum.com/forums...ine-blues.html

I wouldn't buy another GM crate, quality isn't there in my experience. Chinese parts assembled in Mexico. Had to redo the valve train after slighting upping the cam.
I went the crate route for simplicity, if I could turn back the hands of time I'd have a custom engine built, it would have been cheaper and better all at the same time.

Good luck!
So you modified your GM crate motor by installing an aftermarket cam thatís not compatible with Vortec heads, resulting in broken parts and you blame GM?

In fairness, perhaps you should have either done more research or started from scratch with the right parts.




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Old 02-16-2019, 03:38 PM
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PeterC3
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Well, I was relying on my tech's recommendations since I know squat about such things. But everyone was relatively surprised that a mild cam change would break the valve stems like that. I'm told the mod did not exceed the range of the heads, there was not much margin in the strength of the parts.

And yep it's true, doing more research, a second opinion, would have been the wise thing to do. Ya live and learn.... and I've learned a lot in the last few years... :-)
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Old 02-16-2019, 05:58 PM
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Originally Posted by PeterC3 View Post

And yep it's true, doing more research, a second opinion, would have been the wise thing to do. Ya live and learn.... and I've learned a lot in the last few years... :-)
fair enough.

I have about 8500 miles on my GMPP (385/405) crate and beat the snot out of it with no issues to date. Canít beat a warranty!

Good luck with the new bump stick.
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Old 02-16-2019, 07:26 PM
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Several years ago I spun a bearing in my 81. I had never rebuilt an engine before. I got hold of a video tape (I said it was SEVERAL years ago), pulled the engine and followed along with the guy as he did his thing. I had a machine shop clean and bore the engine, install cam bearings, freeze plugs and install the wrist pins in my new pistons and rods. I bought all the parts from PAW in California. I bought all the speed parts such as the intake, plugs, distributor, cam and oil pump from the local NAPA store.
I bought used 70 Vette rebuilt heads and then had a local guy rebuild the alternator and starter. I removed the AIR inlets from the factory stainless headers.
To my great surprise she fired up immediately and after 20 min of break in time I took it to my mechanic for a tune.
The difference in power was very satisfying. I had a little trouble with a crushed spark plug (my fault) but after that she ran nicely.
I bought this used from a local fire chief and he did not know who converted it to a vert. Loved it even with the automatic tranny.

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Old 02-17-2019, 09:12 AM
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Eljay
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I owned an navy/navy 81 4 speed that I sold in 96-97. Just curious about your car, how long have you had it? Where did you get it from? I sold mine in NJ to a woman also from NJ. Any more details or pics?
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Old 02-17-2019, 11:29 AM
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foundvettelifeisgood
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Originally Posted by Eljay View Post
I owned an navy/navy 81 4 speed that I sold in 96-97. Just curious about your car, how long have you had it? Where did you get it from? I sold mine in NJ to a woman also from NJ. Any more details or pics?
I don't think this one is yours. Do you remember your vin?

Last edited by foundvettelifeisgood; 02-17-2019 at 11:47 AM.
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Old 02-17-2019, 12:15 PM
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I have a very similar car as you and I plan on starting with 3:55 gears and see if that helps.
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Old 02-17-2019, 04:41 PM
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Douglas Mariani
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Originally Posted by Big2Bird View Post
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