FWIW,
I measured my old MSD "billet" distributor and the length sticking out was 4.080"
I measured my friend's new MSD distributor and the length sticking out was 4.106"


1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1