You guys got me interest, sooo I dug my 270" [5412 block-477 head]out & it has a piston with a raised hunp on the manifold side of the piston. EBAY item #120351779065 270"+.030 pistons have a concaved top. Will these pistons work with my head? Is my head such a poor design its not pratical anyway? I've done str8 buicks % 6 cyl chev. all my life & still learning, BUT this is the first GMC I've ever owned. Probally just thinking mild street engine, BUUUTTTT? THANK 1 OL REDNECK I.I.#113