I had a similar problem
I made the mistake of installing chrome-moly rings in a 283 years ago...
They never did seat very well and always a wisp of smoke .....
Ever since I use quality cast iron rings in stock rebuilds. No problems.

Some old mechanic types used to tell me ... " put a teaspoon of Bon-Ami down
the spark plug holes & get on it hard ... that'll seat 'em right up ..."

I never had the guts to try that one!!
mike