I have a 408 built by IMM engines. I currently have a port-matched LD4B on it and am making 523 hp @ 6000 rpm and 522 ft-lbs @ 4500 rpm on their engine dyno. I'm planning on installing a Holley Sniper on the car (hopefully before next spring, not sure if I'll upgrade to a Holley EFI Dual-Sync distributor). Is it worth it to replace the LD4B for a Mopar M1 intake (no port work done)? I figure the intake is a big restriction as the LD4B was meant for 273/318's. But how much of a hp/tq increase do you think I'd get? Do you think it will ruin the driveability with the EFI? Crank: Forged Scat 4" Rods: Forged Scat I-beam Pistons: Forged Icon dish (4.030") Camshaft: Custom Comp Hydraulic Roller (card was lost but I believe IMM said it was a 238/242 or 242/246). Lifters: Morel Hyd. Roller Timing Set: True Double Roller Oil Pan and pickup: Milodon Road Race Pan Headers: TTI Shorty Compression: Approx. 9.6-10:1 Heads: EngineQuest reworked by IMM Intake valves: 2.02" Exhaust valves: 1.60" Rocker Arms: 1.6 Intake manifold: Edelbrock LD4B port-matched Carb: Holley 850 DP w/ 1" spacer Total Timing: 34 deg This car will have a mix between cruising and racing (autocross and road racing). Probably 50/50 (respectively) at most but could potentially be 75/25. What are your thoughts?