I used ARP bolts on my engine for maximum strenght. The problem you end up with is the head of the bolts interfere with the exhaust manifolds. I didn't want to leave out the washers (which would screw up the ability to torque them down properly) and I didn't want to grind on the bolt head (which could compromise the strength of the bolt). So we ended up counter sinking the bolt by machining the head to drop the bolt down and out of the way. No field testing yet but looks to me like it will work!