Iīm installing a th700r4 in my car and when I looked at the old th350 there was a big "C"(about 2 inches) on top of it. Whatīs up with that? What does that tell me?

I'm not real sure but in the early 80's they made a th350c tranny which had a locking torque converter for a little bit of improvement in gas mileage.

maybe for Chevy bolt pattern.........

Is there an electrical connection on the case anywhere? If so, it's a TH350C that would have had a lock up torque converter from the factory.

Is there an electrical connection on the case anywhere? If so, it's a TH350C that would have had a lock up torque converter from the factory.

I dont know, Iīll check it out.

i've seen that before. but i can't remember what trans it was on.
does it have a tv cable, or a kickdown cable? i've got one oddball long tailshaft TH350 that doesn't have a lockup plug on it and has a tv cable instead of a kickdown.
itwas in an an 85 GMC 2wd truck.

hereīs a pic of it. Maybe itīs of some help?
http://www.geting.se/image.php/27542-C.JPG (http://www.geting.se/viewimage.php?image=27542-C.JPG)

First Guess: GM has several molds for casting the trans cases. Your case came from mold C.

now i want to see a BOP turbo 350, i wonder if they're marked like that too, just for kicks, i'm going with c = chevy too.