ARP Head Stud Question

[mustang92man]

I just purchased a set of head studs for my motor which has Holley Systemax heads. The ones the place sold me are 154-4005 which says they are for 302's with 351W heads or AFR 185's or Edelbrock aluminum heads. Any idea if these will work ok or do I need the one's that are for the stock heads. I emailed ARP but they didn't have the specs on the Holley heads so he couldn't give me an honest answer. Any help would be great! Thanks...

 

[BK_CAULEY]

if your heads have 1/2" inch holes those are the ones you want. most aftermarket heads have 1/2" holes.

 

[RYC CUKR]

I have a set of Systemax heads and that is the head stud set that I got.

 

[mustang92man]

What could really be the difference besides if they are 7/16" or 1/2"? Is there that much of a difference in length? Also can I just reuse the setup that I have now. The shop that built the motor put them in and they're not really that old. I know you can't use stock bolts over again but does it apply to ARP's? If I can reuse them I will take the new ones back. Besides my local shop raped me anyways. But the convenience of being local I guess.

 

[RYC CUKR]

A stock 302 is drilled and tapped for 7/16" studs or bolts. A 351 is drilled and tapped for 1/2" studs or bolts. Lots of aftermarket heads are drilled for the 1/2" diameter 351 bolts or studs not the 7/16" ones that are in the 302.

The ARP kit that you have should have some stepped washers. The washers reduce the 1/2" hole in the heads to the 7/16" diameter of the studs. That 1/16" doesn't sound like a lot but it is. What you would have to do to reuse the headstuds that you have is get a set of the 7/16"-1/2" stepped washers. The set that you have should have the stepped washers included. I looked them up on Summit and they are ARP part # 200-8598. And they are about $41 for a set of 10 stepped washers.

 

[mustang92man]

Ok, I gotcha. I was thinking that maybe the 351 bolts/studs may have been a little different in length or something. Didn't realize it was just a diameter issue. Yes, they have the stepped washers so that is great. I will take them back and use the credit towards what will probably need to be different pushrods for the new cam when it shows up. Will have to see if I can find my measurement tool to figure out the length I will need. Thanks for all your help.