what engine do i have?
My engine code is (VO0313 FAZ) and on the front outer head is the number 638. I told it was a 305 or 350 out of a 87 chevy truck
The heads belong to a 350ci from around the year that you state. But the only way to tell for sure is to take the heads off and measure the bore. But yeah '638' should be a 350ci.