Did A-B-A tests posi vs. spool several years ago with (1) '67 Camaro Z-28 D/S and (2) '78 Camaro 350 auto J/SA. D/S ran quicker and faster with the spool; J/SA no difference. D/S had a high-zoot posi from Tom's Differentials with billet gears, solid discs, tool steel pin, case girdle. J/SA had a stock GM posi with extra shims.

Just information to throw into the kitty.