Brie----another thing about the 292 Y blocks------the heavier duty trucks---like maybe 2 ton---had 7/16 sodium filled exhaust stems and were quite heavy so don't plan on any sort of high rpm if your heads have them---you can change guides and stem sizes tho and if you mill any off the heads you need to do 150% from the manifold surface of the head to maintain alignment---.060 from deck = .090 from intake surface