[DeTomaso] Another header question: bolts

MikeLDrew at aol.com MikeLDrew at aol.com
Sun Dec 28 18:39:23 EST 2008


In a message dated 12/28/08 15 07 26, cengles at cox.net writes:


>              On the topic of header bolts, does anyone have an opinion 
> about either Percy's Split Lock header bolts or the  Stage 8 Locking header 
> bolts?   
> 

I've seen the Stage 8 bolts, and they seem pretty neat, although I think they 
require a bit too much fiddling around, and of course since you need to 
tighten header bolts after the engine has been through a couple of heat cycles, 
that requires a lot more work.

Personally, I am advocate of ARP small-head header bolts.   These are special 
bolts made with a smaller-than-normal 5/16" head (rather than the more 
conventional 3/8").   You wouldn't think that a lousy sixteenth of an inch would 
make a difference, but brother, I'm here to tell you that it does.   Some headers 
have the pipes exiting the flange at a slight angle, which can sometimes 
interfere with your ability to place a wrench on the bolt head.   What follows is 
an agonizing ritual of turning the bolt 1/32nd of a turn at a time, constantly 
having to flip the wrench to get even a slight purchase on the bolt head.

These smaller heads make short work of this.   The additional clearance can 
be enough to let you get a box-end wrench in there, or a socket--either one 
makes a huge difference.

And they are ARP quality, nothing to sneeze at there.   Once the engine has 
gone through a couple of heat cycles, you'll need to go back and snug them up 
again, and then they should be good to go forever.

Here's a photo from the Summit website:

http://tinyurl.com/8dokeh

Summit doesn't specifically list these bolts as 'small head', so I was only 
able to find them by first looking in my ARP bolt catalog for the part number, 
then typing that number in the 'search' box on the Summit website.

These bolts are available in two lengths; either .750" or 1.00".   My Euro 
GTS headers (and the headers on my other cars as well) have fairly thick flanges 
so I always go for the longer bolts.

They are available in either 6- or 12-point, black oxide or stainless.

Part numbers:

Bolt kit, 5/16" wrench, length .750 

Black oxide 6-point: 100-1108 
Black oxide 12-point: 100-1208 
Stainless 6-point: 400-1108 
Stainless 12-point: 400-1208

Bolt kit, 5/16" wrench, length 1.000 
Black oxide, 6-point: 100-1110 
Black oxide 12-point: 100-1210 
Stainless 6-point: 400-1110 
Stainless 12-point:   400-1210

Entering any of those part numbers in the 'search' box will bring them right 
up on the Summit website.   Cost is $24.69 for the black oxide, 1-inch 
six-point bolts.   Plus Summit charges a flat handling charge, which I believe is 
$11.95 now?

I have actually found that it's cheaper to buy ARP bolts directly from the 
factory.   If you call them up and tell them what you need, they just pop 'em in 
the mail to you, saving on shipping, and the retail price from them is 
usually about the same or even a bit less?

Contact info can be had on the 'contact us' link on the ARP website:   
http://www.arp-bolts.com/

Cheers!

Mike


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