Ok, so I am going from my M6 toTH350 or TH400. From my research I have deduced that:

-A TH350 with 9" Tail WILL work with a stock length driveshaft. Correct?...No modifications to the stock slip-yoke?

-A TH400 will NOT work with a stock shaft, meaning you are an extra $350+ deep?

-A TCI 399753 Flexplate will accomodate a TH350 converter on an LS1? Or do you still need a spacer etc for the pilot snout? Part number?...

**I am leaning toward a TH350 for costs savings with the driveshaft, and the trans beng slightly cheaper. Seems to be LOTS of guys running some serious power through Built TH350s without trouble**

Do you see anything missing from this list?

-TH350 Trans
-Converter
-FlexPlate
-Crossmember
-Dipstick
-Cooler

 

did you read my faq?

 

Of course! Where the hell do I find TH350s with 9" tails? I tried looking at trannys in places like Jegs and Summit and only find 6" tails. Did you forget to mention that its harder to find 9" tails? No, thanks for the FAQ. very helpful!!

 

Just because the stock driveshaft will fit doesn't mean its a good idea to run the stock driveshaft. The stock doesnt even work that well either. My aftermarket driveshaft for my 9" tail th350 is longer than stock. Check out Coan, Rossler, ATI, and the sponsors to name a few for long tail th350s.

 

They came in trucks and vans, they haven't been produced in 23 or so years.
The later ones being the th350C. I used to have a stock pile of different sized outputs and tail housings from th250's, th250C's th350's and th350C's, they're all interchangeable.
Little known fact (I think) some th250's have hollow output shafts that fit th350's but obviously shouldn't be used.

I have a th350C with a 9" tail, it's the spare for my truck, with a custom mount and right yoke it bolts right in place of the 4L80E.

 

I know my 86c10 has th350 w/ 9" tail (stock)

 

No worries on finding a 9" 350! They are out there in abundance.

g

 

I am running a PST 3" alum. shaft and I dropped about $225 on that. I opted for the short tail tranny just for security purposes and I am also using a stock a4 flexplate. I also swapped from a M/6 and I was able to modify my cross brace

 

It All Depends On How Much Horepower U Put Down 500-600 Hp. U Better Stick With The 400 Also The 400 Has A Lower 1st Gear To Get That Car Up An Out Of It Own Way.