my first 400/451 was Indy sr headed & i could fit Hooker Comp headers without too much trouble. with a Hughes flat tappet cam at 256/263, home port job,M1 with 825 cfm carb, 3800 stall on 4.3 rear gears my street 'cuda at 3750lbs ran 10.7@127mph on the 1/4. thats close to what you are looking for isn't it?