Vids of a sbc 350 I built with Edelbrock modified performer heads xe274 cam ran damn good for what it was.That little motor ran best on a 150 nitrous jet in night air 8th mile 7.26.The 421 soft tune same jet 7.03 8th mile.
The 421 was built for a 300 nitrous jet going to creep up on it and see what the 421 will do.