#6223 BB, forged crank question
 

Yesterday went to a big swap meet and picked up two 6223 BB forged cranks. Mortec says they are for a 396 -> 427 so I think I made out ok. My question is what is the difference between all the different cranks that are listed. I suppect that these are just a HD truck crank and not really a hot rod crank.

I am sure that they would be better than a cast crank but they are not as hard I suppect as the 71xx series crank that has been tuffrided. It doesn't say they are cross drilled but they sure look like it to me. The mains have two holes in them. am I just getting too old to remember about these things? It has been a long time since I built a motor.

Pantera

Re: #6223 BB, forged crank question
 

I believe the 6223 crank was primarily used for 396 applications and has a 3/4" thick front counterweight. If the crank is a dull gray color and the mains have been cross drilled (a hole from one side of the main to the other), it would have been used in high performance solid lifter applications. Cranks used in 427 engines use a thicker (7/8") front counterweight to balance the heavier pistons and are forging #71XX. On a non cross drilled crank, the #1 and #5 mains will have only one hole, cross drilled versions will have two.

Paul

Re: #6223 BB, forged crank question
 

Good info, Paul...I believe the hi-po versons got the same treatment as the 7xxx cranks, except for the counterweight. They're a good crank, and the 1/8" counterweight difference is negated with a balance job...less rotating weight with a 6223, which means free power...https://www.yenko.net/ubbthreads/imag...ns/naughty.gif

Re: #6223 BB, forged crank question
 

All BBC # 7114 cranks were crossdrilled & tufftrided from the factory & only installed in original L/88 & ZL/1 427 engines.All GM BBC #6223 cranks that were factory crossdrilled are tufftrided, whether 396 or 427, they came in SPEC HI PERF solid lifter engines only from the factory.
Hope this helps.
Jerry

Re: #6223 BB, forged crank question
 

Fat fingers the forging # is 7115 for the L/88 crank, it was too late to edit when I saw it.
Jerry

Re: #6223 BB, forged crank question
 

I have to agree that the 3856223 chankshaft came in both
396 & 427 applications. It has been found in cross drilled,
and non-cross drilled variants along with Tuff-triding
for the cross-drilled version.

I had always thought that the 427's used a different crank
due to what I read in Colvin's book. However, I have found
many Corvette owners with L/71's that had original '6223
cranks. All the L/72's also used the '6223 cranksahft.

Now, for a kicker, the L/34's also used the '6223 crank,
but it wasn't cross-drilled or tiff-trided. I've heard
that some L/34's were found with cross-drilled cranks, but
they definitely weren't tuff-trided. That was a SHP only
option.

Steve

What more can you tell me about the L-34?? I have Alan Colvins book and I saw a section on the 402/427 where it says the 402 3rd lobe is 7/16". Is this true?? I have a 70 SS Camaro L-34 and trying to verify what crank should be in the block, CTX stamping. Would it be the 6223? The only 6223 I have seen is 3/4" wide 3rd lobe.



Any info on these other 402 cast numbers mark with red dot?


Thanks!

That’s an interesting list … I am curious why the LS/6 wasn’t on it ????