I'am from Fredericksburg,Va I'am building a 1973 Plymouth Duster. I don't know which route I should go with motor wise. Should I build a small block or a big block mopar. Its gonna be a leaf spring car with a 8 3/4 rear end and it has 456 gear. Right now it has 28x12.50x15 E/T streets I know there to big I think. I'am gonna race it but I want to still drive it on the street..