340, 360LA or 360 Magnum?

[70challengerlucas]

Vehicle weight 3,175lbs. Track size 1/4 - 3/8th 12 degree bank asphalt. Compression 9:5-1. Max RPM 6,800. 10” slicks. Stock crank. Stock magnum heads with heavier springs. Springs must have stock O.D. I have a stock 596 rebuilt LA head. Can use roller rockers. Must use a flat tappet hydrolic cam. Intake edelbrock 2176 or mopar 4876335 no modifications or porting. 4412 holley carb metering block 5924/5925 or 10570 with 1” spacer. No modifications except jets, power valve, and remove chock parts and filling of choke hole. Stock Block max overbore 0.040 double roller chain allowed. Headers 1 3/4” x 3 1/2” collector. If I was to go into an additional racing class, it’s the same as above only adjustable rockers, intake 2176 only, and header 1 5/8” x 3” collector. Does that make a big difference in power loss with that combination? Could really use the help, thanks in advance for all the input.