help on TH400 tranny needed
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 4
From: Austria
help on TH400 tranny needed
hi all!
not a Corvette, but i hope for help...
a good friend of mine owns a Caprice, 1970 which had an stock 350HO engine in it. Tranny is a TH400 with shift kit, that gave neck snapping shifts (which he liked), and a 3.42 rear end
now, we upgraded the engine with AFR 180cc heads, Airgap-Intake and a 224/230 110LSA comp cam (08-423-8)
engine is running very strong, but we have some minor problems now:
1) we used the stock Torque converter, and as expected, its not very suitable...
As he don´t like high rpms for cruising, we opt for an 2000 rpm converter...would that be ok?
2) the engine produces lower vacuum, also as expected...
would a vacuum can help much, or will an electric vacuum pump be the better thing? (the brakes were never that good working)
3) the tranny don´t produce the neck snapping shifts like before..i´m no tranny expert, so is this also a vacuum problem, and if so, what will be the solution?
thank you very much for any help!!
not a Corvette, but i hope for help...
a good friend of mine owns a Caprice, 1970 which had an stock 350HO engine in it. Tranny is a TH400 with shift kit, that gave neck snapping shifts (which he liked), and a 3.42 rear end
now, we upgraded the engine with AFR 180cc heads, Airgap-Intake and a 224/230 110LSA comp cam (08-423-8)
engine is running very strong, but we have some minor problems now:
1) we used the stock Torque converter, and as expected, its not very suitable...
As he don´t like high rpms for cruising, we opt for an 2000 rpm converter...would that be ok?
2) the engine produces lower vacuum, also as expected...
would a vacuum can help much, or will an electric vacuum pump be the better thing? (the brakes were never that good working)
3) the tranny don´t produce the neck snapping shifts like before..i´m no tranny expert, so is this also a vacuum problem, and if so, what will be the solution?
thank you very much for any help!!
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
What is his vac reading at idle?
That is not a big cam, should still pull good vac.Plenty run that spec cam without problems
The change in vac could be affecting the trans shift points
2K stall is fine for street use; will allow cam to get into operating range quicker
That is not a big cam, should still pull good vac.Plenty run that spec cam without problems
The change in vac could be affecting the trans shift points
2K stall is fine for street use; will allow cam to get into operating range quicker
Race Director
Joined: Sep 2003
Posts: 16,837
Likes: 338
From: Database Error Indiana
I wold go a 2400 convertor. 2000 is too close to stock, you wont even notice its there. You can tweak on the T 400 governor and get the shift points optimised. A vac reservoir will help the brakes but he may need to do some old school tuning to help also. Maybe he has done that ?? The stock timing setting and curve can be changed to make this new motor do its best.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 4
From: Austria
Hi and thank you!
honestly, i dont know, what the vacuum reading at idle will be, i will have to phone him, and hope, he owns a vacuum gauge,
Yes, i also think, the cam isnt very big, but as i mentioned before, even with the tame cam he had in the stock 350HO engine, the brakes wasnt working that good..
Jackdidley, do you mean this thing? http://store.summitracing.com/partde...5&autoview=sku
Timing was adapted, it runs 12° without, 20°with vacuum connected at idle...the engine seems to like it, take gas smooth and strong
thank you
honestly, i dont know, what the vacuum reading at idle will be, i will have to phone him, and hope, he owns a vacuum gauge,
Yes, i also think, the cam isnt very big, but as i mentioned before, even with the tame cam he had in the stock 350HO engine, the brakes wasnt working that good..
Jackdidley, do you mean this thing? http://store.summitracing.com/partde...5&autoview=sku
Timing was adapted, it runs 12° without, 20°with vacuum connected at idle...the engine seems to like it, take gas smooth and strong
thank you
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Race Director
Joined: Sep 2003
Posts: 16,837
Likes: 338
From: Database Error Indiana
Jackdidley, do you mean this thing? http://store.summitracing.com/partde...5&autoview=sku
Timing was adapted, it runs 12° without, 20°with vacuum connected at idle...the engine seems to like it, take gas smooth and strong
thank you
No, the B&M governor kit is what I was referring to. if you search Summit or Jegs you will find it. Around $35, I think.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 810
Likes: 4
From: Austria
hi guys
time to make an update...!!
for the shifting problem of the trans, simply the carb was too small...changed to a 750 and everything,s ok now...
also, for curiosity, the brakes work fine now..
and finally, we decided to go with a 2400 rpm converter, it drives great....thats the converter, that should be in there from factory!
thank you very much!
time to make an update...!!
for the shifting problem of the trans, simply the carb was too small...changed to a 750 and everything,s ok now...
also, for curiosity, the brakes work fine now..
and finally, we decided to go with a 2400 rpm converter, it drives great....thats the converter, that should be in there from factory!
thank you very much!
Race Director
Joined: Sep 2003
Posts: 16,837
Likes: 338
From: Database Error Indiana
hi guys
time to make an update...!!
for the shifting problem of the trans, simply the carb was too small...changed to a 750 and everything,s ok now...
also, for curiosity, the brakes work fine now..
and finally, we decided to go with a 2400 rpm converter, it drives great....thats the converter, that should be in there from factory!
thank you very much!
time to make an update...!!
for the shifting problem of the trans, simply the carb was too small...changed to a 750 and everything,s ok now...
also, for curiosity, the brakes work fine now..
and finally, we decided to go with a 2400 rpm converter, it drives great....thats the converter, that should be in there from factory!
thank you very much!