which transmission

  1. M20, 21, or Rock Crusher

    I'm putting a 454 Crate motor into my 70 Chevelle SS. It has a 600 lift cam with AFR Racing Heads. I'm running 3.31 rear cog currently but have a 3.90 for a series three twelve bolt carrier which I plan to use. My question is, which Muncie would be the best all around four speed? And if not...