In most apps, I use TS1's.
Eddie

TS1's are a gapless second ring.. I would not recommend using gapless second rings for marine or blown applications.

Ive had great luck with gapless rings. I built 2 406's Using ZGS rings

One for a tunnel hull with C&A zero gap rings and it held up a long time. It was a "mild" build

One 406 went into highly modified silver state classic car that ran flat out-90 miles at a time it had a top speed of over 200MPH.
This build was "wild"

the engine lasted till the owner wrecked the car, and I pulled it out.

Id say from my limited experience and small pocketbook - gapless rings work well.


Uncle Dave

Total seal is recommending a gapless top ring only for marine use.

I used total seal gapless rings (top) in my 1100 hp 540 blower motor, they are great. I also used j/e ring seating compound and my leak down was less than 5% after dynoing, I had alot of guys who NEVER personally used them tell me not to but they were talking out there azz. My first 502 blower motor I used std rings and by 100 hours my blowby was awful, never again!