Ray Y

I'm chasing a blown oil pump problem and it's the first time I've needed to get into this motor since buying the car. Can someone please decode the block and head #'s for me?

Block #s appear to be T1IOICRX and 12B55071.

Heads markings are 3994028, Hi-Perf, F80-71 and
(passenger side GM 2T & kind of clock looking dot set with line and point both pointing to 2)
(Driver side GM 1T, line points to 2 and point points to 12)

Thanks in advance for the help!

Ray Y

Thanks Frank! Ending head digit could be a 6, I scratched across it with the pen trying to decide a 6 or an 8.