Boosted LS1

I'm not very familiar with auto's but am leaning towards a TH400 because it seems to be capable of handling a lot of torque when modded, is light and plentiful. It's for a 427 turbo engine in a retro installation. I know a TH350 fits my chassis. Does anybody know if the TH400 is of similar width to the TH350 in the centre section and is it a stronger box then later GM offerings? 4L80's seem really heavy. Thanks.

twinturbo496

iTrader: (2)

Street car or race only car?

If race only, then TH400 is a mistake. Aftermarket powerglide transmissions are a far better choice for anything less than 3500 pounds in a drag race only car.

If you are going to drive it every day, then the 4L80E is a much better choice than a TH400. OD and lockup converter make a much better street transmission.

Boosted LS1

Thank you TT. It's a road car (Triumph TR7-v8) but very little road use maybe 1000 mls pa maximum. I want to drag race it to get use out of it but retain road car options. The T56 only just squeezes in the tunnel so I need something no bigger then that. I know the 350 fits hence my considering the 400. The 'built' 4L80E I saw the other day looks good but was expensive. I've no idea if the 400 is the stronger box and am aiming for 1000 hp or thereabouts.

crzytown69

iTrader: (17)

if your looking cheap and dont mind winding the motor while street driving it th400 with a trans break

Boosted LS1

The trans brake is the bit that excites me