Have a 312 fastech, looking to install some low boost prochargers and probably 32/34 pitch props. What kind of speed and reliability do you think I can achieve keeping the rpm in the 4600 rpms range? Engines have 425 hrs on them, no problems and don't use any oil. Running Royal Purple.

If memory serves me correctly, 7.4 mpi's (330 hp?) don't have very robust internals. For the money it would take to add the ProChargers, you might be far happier with a nice pair of 502's or 496's. Just my .02...

Exactly what crossed my mind when I read the title to the thread (Procharging 7.4s), before I even opened the thread. I kind of consider prochargers and 7.4s an oxymoron, and there is better ways to spend your money if you want reliability.

As stated this is a good way to get complete brand new motors.....cause the regular 7.4's will not last long with those!!!! Even good 454 mags to 500hp's I'd strongly recommend a re-fresh at 425hrs before adding Prochargers.

The 7.4 mpi's are a workhorse of a motor, able to run lots of trouble free hours. But add some boost to those cast cranks, rods, pistons, non-perf valve train, and you will likely find problems even the Royal Purple oil just can't overcome.