I ran the old RHoads in my 340 and it ran great. Cam was 298 adv and .508 lift. It was a 10.5:1 KB hyper piston motor and with the rhoads lifters it had 230psi of cranking compresion which I imagine bled off with RPM as it had no problem on 93 octane. Ran that combo for years with lots and lots of passes and street miles.