Long time coming, but I'm building a little bracket car
Your goal of 6,s can be reached on pump gas.Use the 408 bottomend,use the Eddy heads(mild porting),4500-5000 stall.Your gear and tire size choices will vary your times.For 1/8 only 4.56-4.88,1/4 4.10-4.30 on a 30 inch tire.Yes you will need a cage to race.No cage if running in the 7,s.