60's were made from '37(tin side) thru '40(bigger bearings), and had 17 stud heads.
I think the '37 had 24 stud heads, stay away from the 21 stud engines, can't find aluminum heads for them.
The 8BA had a more normal distributer and bell housing.
You can cheat and use an S10 5 speed with an Offenhauser adapter and such. I think Speedway Motors sells them. I adapted an old Celica 5 speed into mine. (do not attempt this at home, unless you have a Bridgeport and enjoy beating your head against the wall)