I have an ATI harmonic balancer, but I need a new hub bolt and washer to pin it down. Anybody have a part number or know of the size I need for both the bolt and washer? Where did you get yours? All I know is that the washer needs to be thicker than the stock stuff and apparently, the bolt will be larger as well.

 

I usually use ARP #234-2501. I like the larger hex because it's easier to keep a socket on it if you need to turn the motor by hand. Also, carefully check the length. It's made for a traditional small block and some of those cranks are threaded deeper than the LT1. I have had to trim a few thousandths off the end of the 2501 on a few occasions.

c

 

Perfect!! Thanks cnorton. I searched that and got this:http://www.summitracing.com/parts/ARP-234-2501/

It looks like the thicker washer I'll need to.

 

That's also what I use with my Fluidampr