th400 to th350??

[smoke]

hi.this is my first post.just found this site.and it is sweet.i have had many 73-87 chev's.my question is.i have a 85 blazer.and somebody put a th400 in it was in there when i bought it.well it has gone south.found a th350 with a 203 behind it.what do i need to put the 350 in there?or is it a waist of my time?i would like to put a 350 in it.but they are all 70's that i find.also i would like to stay with the 208 that is in it now.thanks for any help

[VileZambonie]

Welcome to the site... What exactly went wrong with the TH400? That's a really good trans vs the TH350 and if you killed a 400 I'm curious what you use the truck for? You can rebuild a 400 for a few hundred bucks which might be a good idea if you have the ability. You have a 208 behind your 400 now?

[smoke]

it's used just to beat up.kind of a shame cause it's nicer than some i see on the road.but it was way cheap.don't like the kick down stuff on it.so thought maybe a th350.plus it just has the 305 in it still.so thought it would run a little better with a th350.and yes it has the 208 in it.any ideas what to look for to put a 350 with the 208?will the 70's work that have a 203?

[VileZambonie]

So you have the TH400 bolted to an NP208 that someone retrofitted in there? Do you have an adapter for the 208?

[smoke]

ya it's a 400 to a 208.still in the truck.

[Monzter]

Yup, GM used NP208 behind the TH400s. The same NP208 could be used behind the 465 manual transmissions with 32 spline out put shafts too. NP208s are not a very good t-case though. If you get a real smookin' deal on the TH350 / 203 you could add a doubler kit & a 205. This would cost more money, about $1,000 roughly, but is a great set up if you do any crawling in your truck.