I put a GT-40 XB3 crate engine in my 85 GT. Initial timing indicated on the engine build sticker was 10 degrees. I can't get it to run for crap that low. I currently have initial at 28 degrees with 54 total. That seems crazy high to me, but it runs like a scalded cat and doesn't ping under heavy acceleration. My problem comes at mid-power setting acceleration; it backfires like crazy. Floored, it'll put you through the back window, but normal to moderate acceleration causes it to fall on it's face and backfire at about 2800 rpms. Anyone else have decent baselines for the B-cammed GT-40 crate engine? 
