Difference between th350 & th400

[mango86]

Just tryin to get some feedback on the pros and cons of each.I twisted my th350 fri night racing, this is the second one. Running 342 gears at a stall of 2200. The stall is trashed and pretty sure the sprag is toast also. First gear launched great, hit second, went to 5800 rpms and the trans shit metal. The 350 was built to handle aprox 600+ hp. I\'m nowhere near that. Have a option to buy a th400 short shaft for 200.00 . I\'m changing rearends to a 410. any opinions about the difference of these trans is welcome!! Thanks , Vern..

[Scotty_S-15]

For what it\'s worth, a junkyard TH350 should be able to handle a decent 350 motor, so I\'m thinking something was wrong/damaged to begin with.

........ I\'ve always felt that if a trans blows, especially if it was unwaranted, its best not to rebuild it, get another core and start from scratch. I\'ve had good luck with the $599 or $699 TCI\'s from Jeg\'s or Summit. Good Luck!

[my454s10]

a 400 i heard is worse..becuse they are so heavy ..the interals are really heavy...yea a junk yard 350 tranny will hold a lot ...and a mild 350 small block ..should be no problem..if it was a new tranny ..i would start looking at the person who builds them..

[speeder]

I have a short shaft 400 it is nice and shifts faster than my TCI TH350. I have a transgo stick-shift kit in it. It has all heavy duty parts and the sprag is 34 element, so ~1000lbft torque will hurt it. It cost ~600 to build.

[MOREPOWER]

I have a turbo 400 works just fine. Shifts good. no problems.

[FordWizKid]

I had a 400 in my 68 C10 and that thing took a beating. The only thing about a TH400 is that it is less effeicent in transfering power. I think the numbers are 85% for a 350 and 83% for a 400 which is not much however they deff. are heavier and require a different yoke for the driveshaft.

[Knanthrup]

the 400 are monsters and can take a beating but the 350 is more efficient and should be able to handle big power

[mango86]

Thanks to all that replied! I have heard that 400 was not as reliable as the 350. I can get the 350 rebuilt for 200 with guar!

[FordWizKid]

Damn that is seriously cheap. As far as a Th350 being more reliable I do not think that is valid. A Th400 will handle a S$%T LOAD more power then a 350. Remember the 400 is a very popular choice behind a big block, and if it can handle the torque of a BBC then it can deff. handle a small block . Just my two cents...........

[1bad87]

ask any trans builder and they will tell you that the weakist link in a th350 is the sprag.

that would be the first thing for me to change in that trans if I knew I was going to make alot of power.

[speeder]

the TH400 from after 71 has a similar weak sprag, but replacing the direct clutch drum and upgrading to 4L80E drum with 34 element sprag solves that problem.

The 400 can stand brutal wheel-standing torque. The TH350 is strong, but you can ruin it fast. Just pick up any HotRod CarCraft, or even just look under a big muscle chevy from factory. They all have a TH400 from factory behind a big block.

[mango86]

I agree Speeder, but I don\'t think I\'ll have to worry bout wheel stands. http://www.s10v8.com/images/smilies/icon_smile.gif I have my Trans in the shop gittin a high dollar rebuild. Should hold anything I have for it, which ain\'t much, Yet!! Thanks again, I\'ll let ya know how it turns out. Vern..

[loweredd]

You can build a TH350 to handle just as much as a TH400 will. Plus a few people have mentioned that the TH400 does take more power to run. It is more than 85 and 83% difference though....more like 100 for the TH350 to the TH400\'s 85%.

[JayDee]

How can you build a bullet proof TH350 for $200?

I priced the parts and came up with around $400 for parts. Just replacing every factory part with an aftermarket one where available.

[mango86]

JayDee, I never said Bullet proof for 200.00, I said not to bust,and Its who ya know when you get a good price and their rep on rebuilds.I did have my 350 rebuilt and had a new stall built for my trans with the cam specks and weight and butt gears in mind for 380.00,I really expected for it to cost more. Included in the trans, all new clutchs, hardened steel sprag, rebuilt pump and seals Etc. The set up works great, cost me a driveshaft fri night, got that built for 294.00, just have to see what breaks next.