491 Big Block Chevy 635 horsepower on pump gas.
Dart 310 aluminum heads fully ported flow 408 cfm @.700 ,comp cams solid roller 244 @.050 .622 lift
short block has about 750 miles top end is fresh with only dyno time.
Asking $5000 without distributor and waterpump.
So a 420 with 14 deg RHS heads and shaft rockers is legal. I thought this was a budget class by those rules you just opened up the engine range to $18000 if somebody really wanted to win.