273 or 318?

If only my engine looked like that! Lol

I did find and R and 2 in front of the 8490556 after further inspection but still no cid stamp. Still no luck with that number either.

Between all the old oil and grud, the exhaust manifold, and the frame rail, I can’t see squat. I was hoping the stamped numbers would tell me what I needed without getting elbows deep with a wire brush and a pressure washer. Guess not!