Posted by Gerry T. and DIRECT CONNECTION on June 23, 1998 at 10:57:00:
In Reply to: Re: flywheel 440 w/cast crank in 78 p/wagon posted by Dave Hackney on June 22, 1998 at 18:32:21:
Taken from MOPAR Direct Connection Racing Manual - Bulleen #2, 1978;
Late in 1971, cast cranks were introduced in the 383-2 bbl engine and have been used in all 72-76 400’s except some 72-74 400-4 bbl engines. Cast cranks use a specially balanced vibration damper and a specially balanced torque converter or flywheel. They have the same main and rod journals as their forged counterpart.
The 67-73 440 uses a forged cranks of which there are several versions. Standard early 67-70 P/N 2536983. The 70 and 71 440-6 bbl which uses a HD crank with special external balancing because of the HD rod assembly P/N 3512036. And the 72 and 73 440-4 bbl HP engine uses a different crank P/N 3671242. Both of these cranks are forged and differ from the 71 440 crank primarily in the balance weights that are required because of the lighter pistons used in the 72 and 73 engines.
The cast crank was introduced in the 440 in 1974. This crank P/N 3751889 also requires external balancing of the vibration damper and the torque converter assembly. A cast crank engine will have a visibly different crankshaft damper and words “USE W/440 CAST CRANK ONLY” inscribed on the face of damper.
All B/RB engines up to 71 use the same vibration damper, P/N 2658457. The 70 and 71 440-6 bbl and the 71 HP 440 use a specially balanced damper P/N 3512017. This is required because of the heavy duty connecting rods and should NOT be installed on an engine without the HD rods.
Now for you hot rodders, the RB engine will accept the HEMI cranks (426). However, it is suggested that if this is done, use the the appropriate Hemi connecting rods. The Hemi cranks are eight bolt while all B/RB engines, both forged and cast, use six bolts.