I have a couple of J converters one in the race
car and the other in my 416 that was tightened
up by Lenny(Ultimate conv).. its now a 4500 stall
for the street/strip.. I like the J and you can
get it tightened if you want.. that uses quality
parts inside it.. any quality conv shop can work
on it(you dont want some cheapo company putting
in junk parts)