RHS pro action 35010 on 289 - head bolt hole size

markw · #1 (**permalink**) 03-13-2010, 10:15 AM

Hi, just came to fit my pro actions to my 289, and the hole for the head bolts is a larger diameter than the stock heads, do i need bushes to narrow the diameter to better fit the bolts? im guessing maybe this is to allow fitment to a 351 with larger head bolts? though no mention is made of using bushes on the tech sheet?

cheers,

Mark

FASTTECH1 · #2 (**permalink**) 03-16-2010, 11:01 AM

Mark,
Our RHS heads have a 1/2 head bolt hole to fit on the 351 block. It also will fit on a 302, the head will locate on the dowel pins on the block. Our tech sheet does recommend to use bolt part number 154-3605 on a 302 based motor. This bolt it a 7/16 bolt with a stepped washer from ARP. ARP also offers part number 254-3708, which is a special 1/2 machined bolt and has 7/16 threads on it to fit on a 289 or 302 block.

thanks,
John Williams