what I suspect......this is what happened when I first got engine back......it was running very lean and poorly.....the exhaust as it left the tailpipe was so hot, one time when I had a exhaust hose hooked up the hose was close to garage vinyl siding and melted it....
I took off manifold, got a new valley pan and used RTV and that helped a lot..... I cant get any other gaskets other than the valley pan to fit,,,manifold won't line up..... The block was never touched, stock bore and crank before I rebuilt it, the block was decked but only this once.....The heads are unknown as to how many times they were resurfaced.......Hopefully I can get a compression check done today and after that im going to remove the carb, blank off the manifold base.....remove the rocker arm assemblies and but in 5 psi air pressure and listen for leaks underside the intake.......
Im running out of options but im determined