will diesel th400 bolt into a 350 V8 gas with TH350?

[wazzabie]

Will a TH400 from a diesel bolt right into a 350 gas that had an old th350? Would I need to change the flexpate or converter?

 

[crashandburn]

Flexplate, no. Torque converter, kinda. The diesel uses a lower stall speed, so it might go into gear harder, be a little tougher to hold at a stop, and struggle a little bit more taking off. That being said, I don't think it's a huge difference. I have a gas converter in my diesel and it seems ok.

 

[MTBLAZER89]

Yep. The converter is different, but only the fact that its for a diesel I believe. Not sure about the flexplate.

 

[wazzabie]

Could I use the old th36 converter on the th400? If not what would a th400 gas converter cost?

 

[imiceman44]

Could I use the old th36 converter on the th400? If not what would a th400 gas converter cost?

Just get the right converter, if you were using a gas converter on a diesel engine it would be harsh and it will shift on high rpm, but a diesel converter on a gas engine will kill the engine.
Now if you are suing a diesel tranny on a gas engine, and keeping the gas tc then all you need is a different governor.
I could sell you a th400 tc and governor for cheap, or trade you your diesel stuff, just pay shipping.

 

[COCHEV]

I had a diesel th400 behind a 454 for a while and it was just fine. it did stall sooner and shift sooner, but with the rv type cam i was running it was just fine. not sure how it would do behind a 350 tho. I do remember that if i was daydreaming at a light and wasn't fulling pushing the break, it would creap forward.

 

[owenst7]

Just buy a $50 shift kit with new governor weights/springs and a new torque converter at NAPA. They're only $100.

 

[diesel4me]

GM actually installed the lower stall speed converters for diesels in some gas powered trucks too--I've pulled a TH400 out of a G-20 Van with a 292 six that had the six bolt flexplate and the diesel stall speed converter--I've read some recalled trucks that had vibration problems were fitted with the six bolt diesel torque converter also as a "cure"..I see no reason why you cant use a diesel converter behind a gas engine,you'll only use three out of the six bolts,but the pattern is the same (though a TH350 *might* have a smaller bolt pattern)...I know guys who are running a TH400 from a gas engined truck behind their 6.2's and though the stall speed is slightly higher,its barely noticeable--my own '82 K2500 has what appears to be a car or 2wd TH400 case (no brace bar mounts on the flexplate cover,its a tin one!)--might have a gas torque converter in it too,most likely...I've had no troubles with it even after plowing with it for 7 years and giving it a ot of whippings!..

Far as I know the converters from a TH350 & TH400 are interchangeable,provided the TH350 isn't a "lock up" converter model--the non-lockup ones are interhangeable..