327 or 350

[rico7769]

Does anyone know how to identify the diff between a 350 and 327? My casting numbers are 3970010 w/ the other identifying #'s being 5 G 7. I understand the info, but am unsure of the block size. It was put in a 67 GMC CST before I bought the truck. It would make a diff in the horsepower rating we are looking to achieve if it is a 77 and not a 67. Any help would be appreciated. We haven't checked the heads for #'s yet. We are running a perf. intake, holley 4bbl 650cfm, accel hei system, accel 8mm wires, and perf. headers. I am also curious about the HP. If it is 67 it will be greatly diff from 77.

Thanks