I am looking for a shift kit for my TH350 and am looking for any guidance you guys might have.  Here my selection criteria:

I have a stock '81 350 now.  In a few months, I plan to boost to around 300 - 350 HP with a full top-end swapout.

I'd like a very crisp shift, something that'll chirp the tires and push you back in the seat, but the car will never see the strip and I don't won't it so severe that it over-stressing anything else. 

The transmission currently leaks.  However, I have so many things leaking on this car and so much oil and grease on the engine and transmission that I haven't yet identified where the leak is.  When I first bought it 18 months ago, I had a mechanic replace the tranny fluid, filter, and or course pan gasket, but it still leaks.  Anyway... the reason I mention this is that I once read that B&M kits raise the pressure of fluid in the tranny, but Transgo does not.  Anyone know if that is true?  Wouldn't increased pressure increase any leakage I have, assuming I can't totally stop it at some point?

Any problems with shift kits and the lock-up feature of the torque converter on '81 Vettes?

Any advice would be much appreciated!

The increased pressure does not change any leakage factor.  The pressure increase is in the lines and components, but not in the case.    What the increased pressure does is make the clutches and  bands apply tighter.  This prevents slippage under increased torque loads.  It also makes it shift a bit harder.  With the increased HP, I would recommend it. 

The kit with out pressure increases makes the shift firmer, and thereby a bit quicker.  This may pick up acelleration times from the quicker shift, but does nothing to handle the extra torque.

Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thanks Ken and Adam.  One more question (OK, maybe two): My THM-350 takes about a half a second to shift once it feels like it has "decided" to shift.  During that time, you get little accelleration.  I used to have a '69 Camaro with a THM-400 and a shift kit.  That tranny went from one gear to another in an instant.   Ken once responded that the slow shifting was not abnormal for the THM-350.  Is this a poor tranny in stock form or what?  It is the slowness that I am trying to eliminate.  Will the shift kits do that, or will the shift still be slow, but firm once it finally kicks into the next gear?

Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

My opinion on the best shift kit is the Turbo Action kit.  This kit was designed specifically for corvettes as the owner used to own one.

http://www.turboaction.com/frame.html

I would say that 50% of drag racers is using some form of their products.