Header bolt size?
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Joined: Oct 2004
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From: Charleston Illinois
Header bolt size? I think I am just going to get some stainless bolts from the hrdware store to use for header bolts. My question is what is the correct size to be running? I will be running TSP 1 7/8 headers. Thanks
D.J.
D.J.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
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From: So.Cal.
M8x1.25
underhead bolt length: measure how far a bolt threads into the hole, add flange+gasket thickness, subtract 2-3mm, round down to available bolt length (typically a multiple of 5mm)... this will be something like 20-25mm;
e.g. those bolt holes are threaded 16mm deep, my header flange is 10mm, MLS header gasket is 1mm,
this gives: 16+10+1=27 then 27-2=25... so the size is M8x1.25x25;
header flange thickness varies among headers.
underhead bolt length: measure how far a bolt threads into the hole, add flange+gasket thickness, subtract 2-3mm, round down to available bolt length (typically a multiple of 5mm)... this will be something like 20-25mm;
e.g. those bolt holes are threaded 16mm deep, my header flange is 10mm, MLS header gasket is 1mm,
this gives: 16+10+1=27 then 27-2=25... so the size is M8x1.25x25;
header flange thickness varies among headers.
