Ok folks, I just pulled my what was supose to be a 350. On the back where the numbers are. It say's GM 5.0 then other numbers after that. like 3 more after that. Then it has the big serial number. What's the deal. is a 5.0 a 305. I'm putting in a 305 I know that. on theback of that motor block it just has GM 5.0. what'st he deal.