427 L72 COPO Crank
 

I am having a dilemma. From what I have seen/been told, 1969 427 L72 COPO motors came with 7115 crankshaft. I have also seen COPO motors for sale with 6223 crankshaft claiming it is correct for that motor. The little bit of research I have done makes me think that the 7115 crank only came with L88/ZL1 motors. Could someone set me straight on which one came with the motor, 'cause I'm confused...which isn't hard to do. https://www.yenko.net/ubbthreads/imag...mlins/grin.gif

Thanks, Kurt https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: 427 L72 COPO Crank
 

I have a 7115 crank (got it with a #512 block) with smaller counterweights than those on the L88/ZL1-cranks, so there are at least two different types of it.

Re: 427 L72 COPO Crank
 

Chuck [427 King} would know the answer. Shoot him a PM.

Re: 427 L72 COPO Crank
 

The other #512 shortblock I have has a 6223 crank in it. I have never had the chance to look at the crank that is in my original engine in the car, but I thought most COPO 9561 engines had the 6223 ?

Re: 427 L72 COPO Crank
 

i have seen those crankshafts....my memoery tells me that the only difference is the hardening of the journals???

Re: 427 L72 COPO Crank
 

i just found the info.
one is "tuffrite crossdrilled" L88/ and the L72 is "production forged" https://www.yenko.net/ubbthreads/imag...iggthumpup.gif

Re: 427 L72 COPO Crank
 

I believe the difference between the 6223 and 7115 crankshaft forgings are the width of several of the counterweights. I believe the 6223 is 3/4" and the 7115 is 7/8" presumably for balancing the extra mass of the 12.5:1 popup pistons used in the L88 and ZL-1. Knowing how GM operated, the 7115 crank could have been substituted for the 6223 crank based on availability so some 11:1 427's could have the 7115 crank as well.

Paul

Re: 427 L72 COPO Crank
 

My 7115 is 3/4". I think they were used in 402 engines. This has been discussed before, I think mabye a year ago.

Re: 427 L72 COPO Crank
 

Thanks to all who replied. I just sent a PM to Chuck. Hope he can answer the question. From what I have seen, shouldn't be a tough one for him.

Kurt https://www.yenko.net/ubbthreads/imag...ouguysrock.gif