Cast pistons will take 7-8psi no problem,bump on 10psi and you're pushin
it,won't take too much of that for long.
Bob weight is rod big end + rod brgs.+(rod small end+piston/pin/rings/
divided by 2). If you keep it under 6K you should be OK unless you're particularly unlucky
and have a poor OE balance job,(it happens),I wouldn't sweat that TOO much.I would
say do it in a second if money were not tight tho' just the same.
Oh just remember,the cast pistons may take that running the rite A/F &
spark curve,but they'll melt faster than Paris Hilton in the arms of a chance to get noticed
again if they're not !!!