Thanks again for the help, mine are 86mm . as far as the ring type goes i'll take your caution seriously , but this seems to be the next issue where to find rings for these .
I've got a few supplier's that i would normally use but for these pistons they are drawing a blank, as i mentioned above the USA suppliers seem to only list Turbo rings or unclear on NA as they seem to be listed as 1978 - 81 so not the 'series 2' , i'll do some more digging but if you had any suggestions that would be another lead i could follow.