Been going over my 5.7 engine and have a few things to talk about. First one is the heads, seems they can be used on either side, not having to use a left and right. In fact if buying new head just buy two driver side if not using the egr. The reason i tried this i was thinking of using a turbo with the stock manifolds so its just a mater of reversing the heads. There are a few bolt holes to drill and plug the egr hole. The measurement to outside of manifolds is 29 inches, enough to fit inside an a-body frame. I put the intake back on and no issues there and the push rod holes are in the right place. Of course i don't know about the newer heads, just 5.7. The oil passages are a lot of 90 degree turns from the oil pump to the mains so a long carbide burr ball could ease those sharp corners and be opened up a little. This should aid flow to the crank. As i see more I'll keep posting.