[Mark Yacavone]

The J converter was originally made from the Ford Cortina (10 ") core.
Later, this size converter was made from the Toyota core, and then later, the GM 245 MM. unit.
The size business has always been confusing, with some 8 " units (Opel) measuring over 9", and what some call the 9 inch, @ 9.5 or even 10".
The 245 mm GM is the most versatile ,with several different fin angled pumps and stators.
For a while there, the Opel stuff wasn't being reproduced so we did quite a bit of testing with the 245 mm.
Our 400 Pontiac and 350 Buick combos never had anything but, and they ran pretty well.
I feel that we just scratched the surface though, and never got into profiling the various stators.

In any case, if you want to know about J's, call Paul. He's a no BS kind of guy.