I have an RB M1 under my antique Commander 950 Pro TBI. Nothing special 9:1 493 with RPM heads and an MP509.

It fit under the hood of my New Yorker with an Edelbrock chrome air filter assembly. 500 HP/600 ft/lbs.

500 ft/lbs from 2000 to 5000 RPM. Peak was 4000.

Kevin