C2 - 6223 and 7115 BBC crankshaft

[Glenn Ochs]

Can someone tell me the difference between these two big block crankshafts? It seems the 6223 is 396ci and the 7115 is for 427ci, yet all the specs I can find are identical. Can a 6223 be run in a 427 engine? Is one better than the other?

Thank you in advance for any info and assistance you can offer. Glenn

[Joe L.]

Re: C2 - 6223 and 7115 BBC crankshaft

Glenn-----

There are several differences between the "6223" and "7115" crankshaft forgings. First of all, the there is a difference in configuration and thickness for one of the counterweights. Second, all "7115" cranks are cross-drilled. Few, if any, "6223" forgings are cross-drilled.

Third, all "7115" forgings were produced as a finished crankshaft with nitrided bearing journals. "6223" cranks were produced with and without nitride-hardened journals.

Fourth, the "6223" forgings are manufactured from 1053 alloy steel; "7115" forgings are produced from 5140 alloy steel.

The "6223" forgings were used for BOTH 396 and 427 engines. However, the factory balance for the 396 and 427 engines was different due to the difference in piston weight. Consequently, although the forgings (and forging numbers) were the same, the 396 and 427 engines used different FINISHED part numbers for the crankshafts. However, with balancing of the complete reciprocating assembly (which should be performed whenever building an engine) a "6223" forging, regardless of its origins, can be used for either a 396 or 427 engine.

The "7115" forgings were primarily used for L-88 applications. They may also have been used for some HD truck applications, too. It's not inconceiveable that some may have found their way into other 427 engines, too, but it wasn't the "norm".

[Clem Z.]

Re: C2 - 6223 and 7115 BBC crankshaft

we ran non crossed drilled non tufftrided BBC cranks in drag race engines to 7500 RPMs without any failures. we even used 3/8" rod bolts to save weight without failure so any BBC forged crank will stand up as long as you get it magnafluxed to check for cracks. cracks around the oil holes are not a problem.

[William C.]

Re: C2 - 6223 and 7115 BBC crankshaft

Agree with Clem, Same experience in dragracing application, never had a crank failure or problem. Broke lots of other things working up the learning curve, but that's another story...