<VV> piston rings

[Spencer Shepard]

There have some some discussions here on this topic lately and I'm currently involved in a situation where pistons rings could be contributing to a problem. It may be more of a VV topic since it isn't a particularly high performance engine but I know there are some in this group who would have input about this situation. I just rebuilt a '65 110 PG engine. The owner wanted a strong engine for interstate cruising as well as "pleasure driving" and wasn't particularly interested in "high performance". He is happy with the PG (I changed the diff. to 3.27) . He wanted all new parts and and we chose Clarks full-fin cylinders,  "high-tech" pistons, total seal rings and his "260" cam. I was concerned about some discussions I had seen about break-in problems with those rings but went ahead with them anyway. The build was routine using the original heads which were in good condition including the valve guides. Ring gaps were good. Teflon seals were installed on the intakes.  The initial break-in was about 15 minutes at 2000 to 2500 RPM. The problem is the engine smokes. It's especially bad when the engine is hot and really bad if you let in idle for a while when it is hot. Compression is very good on all cylinders and there are no vacuum leaks. The smoke is the same with the vacuum modulator blocked off. It idles very well when cold, has good power and runs smoothly. It stalls at idle when it is hot and is gear.  I can't seem to find the right carb adjustments to prevent that. The carburetors have been rebuilt. I suspect the rings aren't broken in very well. I called Clarks to discuss it and the Tech Guy told me it does take a long while for those to break in. I called Total Seal and their Tech Guy told me that their rings create a higher vacuum and pull more oil through the valve guides. He told me I am probably using "umbrella seals" and I should have "positive" seals on both intake and exhaust and that he has seen tests that show 3 to 6 inches increase in vacuum with his rings. I didn't feel real good about that response.  I'm not sure how much, if any, the pistons and/or cam could be contributing to this problem. I assume the expansion of the pistons is appropriate for the cylinders and the cam profile doesn't adversely affect the idle.  I'm not sure what the next step should be other than driving it and see if it improves. Any suggestions?