400 low buck dont give a

Over probably 20 years I built, and ran, several 400-based combinations. The key is compression. I bought 3 service replacement blocks from a speed shop in Santa Fe Springs, Ca. back around 1987 or perhaps earlier for cheap. These were factory blocks/cranks/pistons. No hole measured less than .108 down. IIRC the worst was .119 down. With a fresh set of 346 casting heads cut 0.020 (do not recall chamber volume exactly....seems like it was in the 92-3 CC aea) compression was less than 8.0 to 1.0. I used a cast replacement 440 low compression piston with the piston deck milled for a zero deck w/valve reliefs. I think by the time all was said and done they sat at 0.003 down. The rest of the combination was a set of pocket ported 346 heads, torquer intake, 750 AFB carb, a Crane cam with a .112° centerline and .454 I lift, .480 E lift, a set of Hedman 1 3/4" tubes with 2 1/4 exhaust system in a '78 Dodge half-ton PU. It would smoke the tires at will with street tires and 3.55 gears. It ran mid 13's with 4.10 gears and a set of worn out 9" slicks and, if you kept your toe nails off the radiator, pulled down 16 MPG at a steady 60 MPHwith the 4.10 gears. Point is, they can be made to run for not much more than a 440. I like them for A body cars simply due to the exterior size and lighter weight over a 440.
My two cents worth........
Bob