[ProGSX]

Are some better than others, what to look for?

 

[miclau]

some say the 8 bolt front pump th400 is stronger than the 6 bolt but everyone has there opinions. I am looking for an 8 bolt to replace the eight bolt that i destoryed so i can reuse the front pump

 

[69GTO]

I've found cases from Cadillac and full size cars to be much stronger.........

 

[jackson]

my th400 chevy case only has 6 holes but, there plenty of meat to drill and tap the case for the other two bolts if thats what your after.

joel

 

[slowstang]

i have an 8 bolt trans its a 1967 model fresh but has been sitting for 5 years anyone need it ? its stock with a shift kit

 

[LEAVNON3RD]

my father and i own a transmission shop, and from what ive seen its pretty impossible to answer. yes some fo the earlier th400's like in a long tailed caddy seem to somewhat have some extra beef in the case. and in every severe duty application we have always used the 8 bolt pump's. but never had a non 8 bolt fail(other then it beign a rebuilders fault). im unsure how early back it will go but some cases are molded with a "HD" on the bell. id assume it meant heavy duty. the seem to come in truck applications both 2wd and 4wd. iv used both cases and never saw any hard proof that one is really better then another. i had a case stamped "HD" in my camaro and blew the case apart after a season with street miles, and have a non hd case for 3 or 4 seasons with alotta abuse/passes/streetmiles and still holds strong. both transmissions are set up similar. this is with a 3800lb camaro in the low 9's on spray. not as fast as most of you guys but at 3800lbs the titanic wasnt fast neither.



there is only one better case that i have seen that i could say is really overall better, and it is super rare. some cases and a set screw to hold the center support. its help alot but are almost impossible to find these days.

 

[jim sciortino]

Where is the aftermarket 400 case???

I can't believe with all the high powered cars running 400s, there is no SFI case.

 

[Twotontird]

I've never seen any difference either. Some say some are thicker....I've measured ...no diff. just the ears were thicker

 

[frtlnrbuick]

Here's what Hutch has to say about the thicker cases:

Gussets up at the top of the pump surface , likely an 8 bolt or has 8 bolt bosses , double rib between the VB and the tail and has no bumps by the vent and upper pump bolts.
Hutch

Yes, there are thicker cases. They are all BOPC cases, IIRC, certainly have never seen a Chevy case like them. They have several distinguishing features, including ribs between the top bolt holes, and ribs from the valve body rearward toward the tail on the inside, and what Hutch said above.

Don't know exactly what the difference in strength might be.

Jim

 

[LEAVNON3RD]

accroding to ATI and dedenbear, they both hinted to making aftermarket th400 cases over 2 years ago when i spoke with both companies at sema/pri. havent heard any update or news since. they are wel aware of good th400 cases and becomign scarce.

 

[fastone371]

Some Chev 400's have thicker webbing around bellhousing area, not sure if there are any other differences between the 2.

 

[Limey tri Chevy]

Wait till the stock 400 cases are all but gone then start casting / marketing thier own SFI ones at much higher prices than they could do now while they (stock cases) are still available. Cynical thinking or just good business sense?