What heads studs do I need?

[Black1987Stang]

I'm ordering stuff for my 331 buildup, what studs do I use, what's the difference? I don't know what undercut means or what size does the 302 use....it's a 302 block, with Trickflow twisted wedge heads

http://store.summitracing.com/egnse...2+4294840126+115+4294862534&Ntk=KeywordSearch

 

[RYC CUKR]

The 302 block is drilled for 7/16" heads studs or bolts. However lots of aftermarket heads are drilled for 1/2" head studs or bolts. Check the specs on the Trickflow heads and see if they are drilled for 7/16" or 1/2" studs. If they are drilled for 7/16" then the part # is ARP-154-4001 if the heads are drilled for 1/2" studs then the part # is ARP 154-4005. The kit for the 1/2" holes has stepped washers that fit in the bolt holes in the heads to reduce them down to 7/16" so that everything is correctly located on the deck.

FWIW the aftermarket heads are drilled for 1/2" so that they can be used on 351Ws without having to be modified by a machine shop.

 

[Black1987Stang]

The 302 block is drilled for 7/16" heads studs or bolts. However lots of aftermarket heads are drilled for 1/2" head studs or bolts. Check the specs on the Trickflow heads and see if they are drilled for 7/16" or 1/2" studs. If they are drilled for 7/16" then the part # is ARP-154-4001 if the heads are drilled for 1/2" studs then the part # is ARP 154-4005. The kit for the 1/2" holes has stepped washers that fit in the bolt holes in the heads to reduce them down to 7/16" so that everything is correctly located on the deck.

FWIW the aftermarket heads are drilled for 1/2" so that they can be used on 351Ws without having to be modified by a machine shop.

Thanks I just measured the heads and they are 1/2 holes.

But don't you mean 254-4405 for the hex and 254-4705 for the 12 point?

The one you listed 154-4005 doesn't say undercut and doesn't say anything about 1/2 where as the other 2 does, and they are more money, to pay for the stepped down washers...

Someone please clarify this up I want to order them right now

Thanks