I've been looking around for a 4.250 1 pc. crank to go from 502 to 540. My block is GM (ZZ502) so I gotta go with the 1 pc. crank. I'm finding that the 1 pc. cranks can be hard to come by.

I'd like to go with Callies, Crower, Lunati, something USA made. And hopefully in the $1,000 to $1,200 range.

Any dealers or suppliers here at OSO that have them, or can suggest who to contact about a 1 pc. 4.250 ??

Thanks !!

btw, I posted on this subject yesterday but something wierd happened to my computer, and my post got gone, along with some other stuff....wierd

you can use the two pc. rear main seal old still gen. 4 crank there is a drop in adapter made to fit that block so you can run the two pc. seal i have used them many times with good results no leaks at all on high output motors i thank scoggens ****ey chevys them

I called Callies to look into the availability of a 1 pc. 4.250 Dragon Slayer. Guy at Callies said they produce very limited numbers of the 1 pc for the GM BB. He also mentioned the adapter. But said they can leak and they were not a good idea in a boat because of possible leaking. Another guy told me the same thing about the adapter. That's why I'm a little leary about using one. Keep in mind, I know nothing about this subject, other than what I've been told. I'll ask my engine guy if he's used the adapter and see what kind of luck he's had with them.

Thanks mikes280

I Run The Adapter In Mine I Have'nt Had Any Leaking From Mine Yet It Has 3 Years On It

I would definatly use the adaptor. One piece has a large diameter seal and so you get a much higher speed where the crank meets the seal. Useing the adaptor the seal is much smaller and a lower friction speed. Means more reliable seal. And cheeper cranks. I have been led to beleive they are very reliable and dont leak if installed well, Jas

We are a Callies dealer if you have problems getting one give me a call.
Thanks Mike

Roccard MArine Engines
www.roccardmarineengines.com
[email protected]
570-956-2840

Thanks for the replies everyone. I'll get in touch with my engine guy and discuss using the adapter. Sure would make finding a crank allot easier.

Thanks again !!

Wow, I thought 1pc cranks would be easy to find given how long the blocks have been around.

I used the adapter for a "old style" two piece seal in my 502 block. I never had any issues with leakage...