Something isn't right... Pulling the heads and a degree wheel may be the only way to get it back where its supposed to be. I'm now questioning whether your cam is running advanced or retarded? Or there is a issue with your timing chain? Maybe start by pulling the timing cover instead of the heads. Check your timing setup. Stock cam, dowel pin at 6 o'clock, #1cylinder TDC. Stock crankshaft, keyway at 12 o'clock, #1 cylinder TDC.