If your seriously thinking of the GM v6 swap, I would definately convert to cv joints. The outer cv joint is locked to the hub and axle, but the inner end attaches to the tripod only. The cup attaches to the diff output. The key to adapting cvs is to ensure the tripod doesn't bottom out in the cup with the suspension compressed and/or come out of the cup with the suspension hanging down, weight off of the wheels.
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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS
viewtopic.php?f=5&t=13225&p=134742Simple Spring select
viewtopic.php?f=5&t=11815LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12