Is there anyone out there with one of these old school rides it is an ls 272 formula 1986 and i am running a 14.25 diam prop 21 pitch and it has alpha one drives 1.50 gears with twin 350's in it trying to find the right prop for it it will run 49 mph at 3900 wide open any answers on this thanks

You need a 19 pitch prop tp bring up your RPM . I had a 87 272 with 350 mags 19 pitch props 55 mph at 4400 rpm.

what dia prop did you use 14.25 ?with 19 pitch prop

14.25 but a 383 with 425 hp with a 23 pitch 14.25 will get you to 69.8 on GPS @ 5100 rpm

thanks