O.K. the heads had to come off my newly acquired 390, because the exhaust manifold bolts, the last two either broke or wouldn't come off the head. I purchased HP books manual on FE rebuilds. The head code indicates '68 mercury with either 4v or high compression 2v. the cast iron manifold turned out to be a 4v w/ a 2v adapter on it. (of coarse I just traded my 351W edelbrock for a 390 edelbrock performer.) I guess I will enjoy a lighter perhaps better manifold w/ the edelbrock. Any Idea's what the Iron manifold might be worth and how to sell it? The disassembly revealed a recently rebuilt engine w/ strong clean heads and bores and pistons. Very little Carbon, no ring ridges at the top of the bores. It also revealed a bent pushrod and a corresponding cylinder full of gas. The exhaust manifolds seem to match the heads code wise as for a small engine compartment (Comet, or Cyclone) The intake manifold indicates GT. I guess I will continue cleaning up the motor while awaiting machine work on the heads and manifolds by removeing the water pump, and timing cover and inspecting the timing chain. Any heads up on potential problems with disassembly? The passenger side exhaust manifold has a heat valve at the end of it. Is there a spacer available to replace this as my carb has electric choke? Interesting day today.