Originally Posted by majorownage
Arp hardware and 2 bolt studs. He says the caps have more area to contact the block, and are therefore more stable and less likely to walk. With two more extra holes in the caps, there is just not enough contact area between the block and the cap.
With a splayed 4-bolt cap, the register for the cap is lengthened to provide more surface area than what a 2-bolt cap has. The register is lengthened the same amount that the 4-bolt splayed cap is longer, in other words.
While using ANY OEM block for high HP builds is risky, I don't see a stud and 2-bolt cap comparing favorably to a splayed 4-bolt studded cap.
Now, if you were talking about a 400 SBC...