TH400 vs TH350
Thread Starter
Heel & Toe
Joined: Jul 2007
Posts: 24
Likes: 0
From: Jacksonville Florida
TH400 vs TH350
Hello all!
I bought a 71 from my uncle and he had a TH400 in it with a shift kit. He also gave me the TH350 it came with. After reading several threads I see that many of you say the TH400 takes HP away from the performance. I have gone through everything from the suspension to the engine and drive train except for the tranny. It doesnt feel right to me so I am going to have it reworked at a shop. My question is would I be better off reworking the TH350 or the TH400? I am running a 383 stroker, a 750 Speed Demon Carb and 290 gears in the rear end. I have already spun the drive shaft so I bought a heavier one from Ecklers.
Any ideas would be appreciated!
I bought a 71 from my uncle and he had a TH400 in it with a shift kit. He also gave me the TH350 it came with. After reading several threads I see that many of you say the TH400 takes HP away from the performance. I have gone through everything from the suspension to the engine and drive train except for the tranny. It doesnt feel right to me so I am going to have it reworked at a shop. My question is would I be better off reworking the TH350 or the TH400? I am running a 383 stroker, a 750 Speed Demon Carb and 290 gears in the rear end. I have already spun the drive shaft so I bought a heavier one from Ecklers.
Any ideas would be appreciated!
Last edited by RBRUTLEDGE; Sep 28, 2010 at 10:36 PM.
Melting Slicks
Joined: Oct 2008
Posts: 2,154
Likes: 69
From: Regina Sk Canada
The 400 has a 2.45 ist gear and the 350 has a 2.54 ist gear. I built a th 350 to handle 600 hp, the th400 is pretty much bullet proof out of the box. I would leave the TH400 in the car less hassle down the road.Plus its a factory piece so it all fits correctly.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
T400 is 2.48 1st gear, T350 is 2.52 1st. T400 definetly eats some power but is a direct fit, your electric kick down will still work and you can use your regular front slip yoke. Not to mention it's much tougher.
Keep the T400, basic rebuild with good clutches, 34 element sprag and Trans Go shift kit and you're good to go 10s.
Keep the T400, basic rebuild with good clutches, 34 element sprag and Trans Go shift kit and you're good to go 10s.
