I'm looking to get new ARP piston rod bolts and I see there are two that are listed in their catalog for my block. The part numbers that apply to a 351W are 150-6004 & 154-6006. The difference is in the head style. One is round and the other is mostly square. Does it matter which one I get as a replacement? I guess I am not sure if I need a specific bolt or if I could use either of the two.

Thanks.

 

What connecting rods are you using?

 

I found the answer after I removed the pistons from the block and I can now see the top of the rod bolts. I have an oval style head so I'll stick with that as it seems the rod is shaped to only accept this type of bolt head.