Engine Guru\'s (383?) Here's my question. I recently bought a friends truck with a 383.. It has a Scat crank, Manley Rods, KB Hyperu pistons, Trick Flow Twisted Wedge heads, stock 89 block, Edelbrock intake and carb... The engine was built to run an EFI.. But my bud swapped on a carb after he got tired of playing with the comp stuff. When originally built he told me it had about 10.5:1 compression. ABout 1 year after he built it, he burnt a valve and the builder resurfaced the heads. Now he thinks the compression is about 11.5:1 or 12.5:1.... Withthe timing set where it should be it pings bad on 93(thats a given), but he retarded the timing(he says 13*) and now you can run 93 in it and have a very slight ping under a heavy load. My question is, is this doing harm to the engine? I know the pinging isn't good, but what about running so much retard in the timing? Thanks!