GMGT's new powerplant

[mrltd]

he can make it up with gear. gonna be running the manual tranny anyway...

[PatsPOS]

Quote:
Originally Posted by PatsPOS
All this talk about engine, and I'm just amazed to see a heavy-duty small-block C-6.

I have more BB HD C-6s than any one person should have...didn't even know they made a HD SB C-6!



Are you calling it HD just because of the ribs on the case? It looks like any other early SB C-6 to me. The main case is not a weak link. The ribs do not reflect the internal configuration.


This may sound like a dumb question, but why would Ford use two different cases (one with ribs, one without) in the same model year if the internals of the tranny were the same? The reason I ask is I have access to two '72 Mark IVs; one has the reinforced case, and the other does not.

As far as Tom's cam selection goes, I vote for the 234º/244º split-duration cam...as others have pointed out, it's way too much cam, but just about the least amount of cam that will work with an engine with a 10.5:1 compression ratio.

Now if the compression was to drop to 10:1, then I'd suggest a nice 234/234 cam.

Pat

[Mercracer]

This may sound like a dumb question, but why would Ford use two different cases (one with ribs, one without) in the same model year if the internals of the tranny were the same? The reason I ask is I have access to two '72 Mark IVs; one has the reinforced case, and the other does not.

Look at the casting numbers. Often times, parts are just grabbed by what is available, not some grand deliberate scheme. If they are both from the same model and year of car, why would one be more or less heavy duty deliberately? The tag on the side attached to the servo cover will tell you the intended application of the tranny. It is possible that over the past 35 years that one of the trannys was swapped out.
Looking at the larger picture, I haven't seen a transmission case fail at the point of the ribs. Either the bell ears are busted off or the tailhousing is cracked.