Big Blocks

This section will cover the Big Block Dodge engines 400s and 440s as the 383 is very close to the 400 with the bore being different only, as they share the same stroke and rod lenghts. The 440 was chosen because of the number of people that have them, the specs will apply to the 413 and 426 engines also as they all share the same strokes and rods, with the bore being different only. First the 400 engine.

Engine: 400 .020 with low compression 440 pistons
Compression: 10.83
all accessories installed
Heads: typical 70s production
Valves: Int. 2.08/ Exh. 1.74 with bowl porting on both sides
Intake: M-1
Carb: 780 vac.
Exh.: hedders 1 3/4" with 2.5" mufflers dual full exhaust rated @ 540 cfms
Camshaft: Comp cams 280H lift .480 with 230 duration @ .050
Octane: 89

Peak HP: 385 @ 5500 rpms
ave. HP: 316
Peak Torque: 409 @ 4500 rpms
ave. torque: 329

The reason for the 440 low compression pistons is before the KBs were around this is what had to be used to get the compression up with out buying a race piston. This engine would give a mild sound and great performance, pretty much a copy of the Road Runners of the late 60s.

Now for the 440.


Engine: 440 .030
compression: 11.76
all accessories installed from the 70s less A/C
Heads: typical 70s production
Valves: Int. 2.14/ Exh. 1.81 with bowl blending
Intake: M-1
Carb: 780 vac.
Exh.: Hedders 1 3/4" with full exhaust rated @ 540 cfms
Camshaft: Mopar P4120235 is a .484-284
Octane: 93

Peak HP: 395 @ 5500
ave.HP: 298
Peak Torque: 428 @ 4500
ave.torque: 322

This is pretty typical of the 440s of the 70s with some performance mods done. The engine is down on power and torque some due to the size of the valves. With the stock size valves the engine will respond better and produce better on the street, but this was just to show that the bigger valves on the street sometimes doesn't work.
Either engine should be able to run in the 11s in a A-Body with the chassis to go with it. This is just to also show that these engines can be run on pump gas even with compression. But if the cam is changed (to a larger one)then the compression will have to be reduced.


BJR Racing