The numbers you are looking for should be stamped on the 'pan' itself, assuming it's got it's original pan and it's a Chevy 350.
Buick also built TH350's .There should be a 6 digit # on the right vertical face of the pan.
If you can find these #. Post them and I'll see if I can decipher them for you! As 'Hotrod' said 350c's have a connector just near the shift linkage.
Jock.
You may also find marks on the bellhousing. Usually 1# and 2 letters.
