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strong transmissions


Matt M

Hello all,
I am new to the world of OHV engines. I have been into turbo imports since 97 and recently got a deal on a 76 corvette I couldn't pass up. So now I own a vette, which I know very little about. Well heres the deal. If the numbers aren't all matching I want to modify it and occasionally drag race, but I want to use only the most reliable parts. What are the stock limits on the transmission and what are my options? I am on a budget but will buy the best if it means it will run forever :). Are there any better transmissions which are easy to swap in? Any information will be greatly appreciated!

Matt Miller
1976 corvette
1992 3000GT
1993 Talon TSI AWD
You didn't say if you had an automatic or a manual transmission. If you have an automatic it would be a Turbo 400. It can be built up to handle any amount of horsepower that can be made with a small block engine.
I can't help you if you have a manual.
Good luck with it.
Hey Matt,
Welcome. I also enjoy imports and domestics having a WRX and a 78 vette. Unlike Troy I know zippo about automatics but a middling amount on manuals.
If it's a manual it's a M-21 Muncie. It's bulletproof and will handle
most anything you through at it. The problem you will have is with the rear end cover,the u-joints and the clutch.
I am overpowering my brand new Zoom 10.5 inch street clutch with moderate launches.
I'm not sure if your year has a 10.5 or 11" clutch but if it is a 10.5 you should upgrade to an 11" clutch. I don't know yet if this requires a new bellhousing but I'll let you know as I'm in process with this modification.
You should also get an aftermarket rear end cover. Check out Strange Engineering for a real super duty number or Vette Brakes and Products for a Street duty peice.
Solid U joints are a must as well (no zerk fittings).
Lastly Denny's Driveshafts are a good source for strong aluminum halfshafts and driveshafts.
If this going to be a drag car you might want to check out GearVendors for a electric overdrive which takes the place of the tailhousing on the M-21. Instead of hitting fourth gear at the end you can split third and fourth by engaging third overdrive without using the clutch.
Good luck.


If you have the 400 trans there is no need to worry about it's strength. My son has a motor home with that trans and he pulls his race car all over Florida with it. The only problem is that there is no overdrive and the gas mileage kills him. A good replacement would be the 700r4 with a shift kit. That will give you a strong tranny with overdrive.

If you have the Muncie M-21 4 speed, that also is a strong box. Again, no overdrive. Think about the six-speed.

It all depends upon what you want to do with it.

If you have the TH400 auto, as greyghost said you will have no problems, they are almost indistructable behind anything a smallblock can throw at it. The four speeds are the same, my 81 has seen three summers of hard racing at the strip and nothing has broken yet although I have just replaced the clutch this weekend in time for the next meeting. The flywheel was almost completely blue with the heat !!!! and I have fitted a twin plate Quartermaster set-up.

The stock running gear with a decent clutch should be good for 300 - 400hp without to much problems.

Welcome to the CAC Matt and more importantly welcome to the world of glass wrapped small blocks. You'll enjoy both!

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