He's wrong, that was the previous gasket unless I missed another service bulletin. Just grasping at straws here, any chance the cam is not in (timed) correctly? Trying to find a reason for reversion if you don't have an actual leak. Do you have someone who can surface the manifold & riser?

Never degreed the cam. Used a cloyes timing gears/chain and set it to the stock setting. I guess I can take the manifold to the machine shop and have him mill the surface. When I prepped the risers I used a sanding block and all looked good straight accross. Just noticed the pressure gauge dropped 3-4 lbs since noon today.

Marc, If the timing chain was'nt timed correctly... would there be any other indication other than reversion? Initial timing is set at 8 degrees and distributor appears to be in the exact position as the other engine.
Stan

In case this may help someone I found the problem. The exhaust manifold was warped where it bolts to the riser. I dressed up the suface using a file very carefully until it was decent. Been using the graphite Merc gaskets same as the other side and have not had a problem with them. In this case I used the paper gaskets with hi-temp silicon and solved the problem.
What stumped me is when I freshened the engine I left the risers attached to the manifolds to avoid something like this. It was not leaking prior to the fresh up and was driving me up a wall.
Marc and all, thanks for the input, Stan.