i talked to a transmission guy and told him about my problem with my trans.
the trans is not shifting out of 2nd at all but if i put in lo the engine revs high before it will take off then i can shift to 2nd and thats all i got he told me a few things to do to try to fix it 1 is to adjust the band, but anyway we were trying to figure out the trans type i told him it was a c4 case that is what it seems from the shape of the pan but he said that the rectangle filter was in a c5 but the auto parts said that they had 3 different filters for a c4 cause the 1st one they give me had several bolts where as the one i has only had 1 blot in the center and the trans guy said the c5 had a bad design and there was something can't remember what but something that would go out all the time so i was wanting to know what kind of trans i should put in here, i was going to get mine rebuilt but if indeed it is a c5 with a bad design then i want to go with something more reliable my truck is a 78 f100 with a 351w a/t, it came with a i6 and manual trans. which i would like to have the manual trans back on my 351 but have been told that it would be hard to find a manual that the bell housing would match up to

 

C5s were in Bronco IIs and maybe some Rangers.
C4s were behind 302s, and the 351W has the same bell pattern, so I'm sure it's a C4
The C4 also has the square/rectangular pan.

 

I had a difficult time reading that (no punctuation)

a c5 is a c4 with a locking torque converter. When they get rebuilt, they eliminate that portion of the c5 making it a c4.

the I6 and 351 share the same belhousing. Finding the small block belhousing is not impossible, just tougher.