ARP Header bolts
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
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From: So.Cal.
On an LS1...? No, you need metric bolts: M8x1.25x20 or M8x1.25x25 depending on header flange thickness.
In ARP catalog, on page 81, see these part #'s:
661-1001, 671-1001, 761-1001, 771-1001.
661-1002, 671-1002, 761-1002, 771-1002.
You should measure the hole depth first (including header flange), you do not want the bolts to bottom out in the holes.
Hole depth is threaded to 16mm, and typically on good headers the flanges are 10mm or thicker.
In ARP catalog, on page 81, see these part #'s:
661-1001, 671-1001, 761-1001, 771-1001.
661-1002, 671-1002, 761-1002, 771-1002.
You should measure the hole depth first (including header flange), you do not want the bolts to bottom out in the holes.
Hole depth is threaded to 16mm, and typically on good headers the flanges are 10mm or thicker.
Last edited by joecar; Nov 10, 2009 at 08:26 PM.
