Only physically the same, there were different shafts for different HP ratings. The low-perf 396's had cast cranks, the hi-perf 396's had steel (#6223). The low-perf 427"s had steel (#6223), but the hi-perf 427's with the large rod bolts had "heavier" shafts (#7115). These were cross-drilled as well. Many of these steel's (mostly in the hi-perf builds) were "Nitrided" from the factory. Thanks, Gary in N.Y. P.S. There were other forging numbers available but these were the most popular. They were all balanced for their respective applications. The 7115 shafts had more material in the counterweights to make up for the heavier rods/pistons.
I do not think that the 396(6223) were cross drilled from the factory. Around here to have one Nitrided is around $100.00
yes and no. GOSFAST is on the right track, if you run stock replacement 427 pistons or pistons that weigh close to the same), it will need a slug of mallory metal to balance.
It wasn't mine, it was for a motor I built for a guy, and to be honest, I cant remember. It was about 15 years ago anyway, so it wouldn't help much. It only took one piece, and we used brand-new TRW L2268's so that should tell how long ago it was!
From chevellestuff.net 396/402/427 - 1965 through 1972 The 396 crankshaft is the same as the 427 crankshaft except it is lighter due to the counterweight design. The third counterweight on a 396 crankshaft is 3/4" wide, the 402 is 7/16" wide, and the 427 is 7/8" wide. Prior to 1968 all 396 crankshafts were forged steel. In 1969 the lower horsepower engines used a cast iron crankshaft. All 1965-1967 427 crankshafts were forged steel. For 1968 & 1969, only high performance 427s used a forged steel crankshaft where low performance 427s used a cast iron crankshaft. From mortec.com BBC Two-Piece Rear Main Oil Seals 3.76" STROKE (used on '65-'90 Mark IV 366T, 396, 402, 427 or 427T) 6223.......396,402,427...forged, 1053 steel 7115.......396,402,427...forged, nitrided, cross-drilled, 5140 steel 3804816....396,402,427...cast 3856223....396...forged 3863114....402... 3863144....396,402... 3874874....396,402... 3879621....427...forged 3882841....396...forged, cross drilled, nitrided 3882842....427...forged, cross drilled, nitrided 3882847.... 3882848.... 3882849....427...forged 3887114....396...forged, nitrided, 5140 steel 3904815....396,402...cast, nodular iron 3941180.... 3942411.... 3965746..........semi finished, forged 3993804..........raw, 5140 steel My first car 40 years ago, was a '66 Chevy with a 325 horse 396. It had a forged crank (and was the first engine I ever rebuilt)
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