Header Bolt Length Question??

95PGTTech

Member
Jan 28, 2008
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Hey its Adam95GT,

Im putting on the accufabs i bought and the fitment looks great... i have a set of brand new mister gasket .75'' headerbolts... but once through the flange and gaskets there doesent look like there is much thread left. Should i order a set of 1'' long bolts or go on with these??? There looks to be about 5 complete threads showing... I have alum. heads i just dont want to strip them out. Stripping bolts is my biggest fear... sad nut true... also anyone know the torque spec for header bolts on alum heads?

Thanks guys,
Adam
Ones i have:
http://www.promustangperformance.com/mrg-919g.html
1''
http://www.summitracing.com/parts/ARP-400-1210/?rtype=10

Hmm... i think i might be stuck with .75'' bolts... the .75 just barely bottoms out on the head with like one thread left... the flange thickness is only .25'' so if i go 1'' they will probably bottom out... i dont want to count on a gasket to make up for any difference.. and its too tight to get a washer on a header bolt.
 
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First see how far they thread into the head, and how much thread you have left. If you have aluminum heads, you need a lot of bolt going into the heads. Aluminum threads pull out really easy. I've fixed at least two threads on my heads, and one needs a helicoil now.

Kurt
 
First see how far they thread into the head, and how much thread you have left. If you have aluminum heads, you need a lot of bolt going into the heads. Aluminum threads pull out really easy. I've fixed at least two threads on my heads, and one needs a helicoil now.

Kurt

exactly man...

Well here is the deal... i have a little less then .75'' thread in the heads... the flange is .25''

So that means a 1'' bolt will bottom out.:nonono: so i cant go 1''

However, i found some 7/8'' bolts today! from some elcheapo company at pepboys. they look like they will work fine.... i chased all the threads with a bolt... one has some junk in the threads and i cant thread it by hand...


I tried to blow the threads out.. only to have the blow gun pop off the air line and cracked my windsheild! :rlaugh:

But yea it will thread in if i put a wrench on it doesent take alot of pressure. I just think there is some dirt in the threads... Im not seeing any metal on the threads or anything and the bolt is just getting to tight to thread by hand.

its deeper then the bolt will thread with the header bolted up anyway.

Im gonna use these 7/8'' bolts they get me an extra thread. george told me to just use high heat RTV and no gasket
 
I would take a tap and clean that thread out. Whenever I take any engine apart, I go through almost every bolt hole and clean them all with a tap. It really helps keep all the threads in the engine in good condition, and saves yourself from gubered up bolts. You're going to find that it's real easy to cross thread one of those header bolts if the header flange isn't perfectly straight. It's not a bad idea to get some studs to mount the headers with. Sounds like you are on top of things though. Except for the windshield, that totally sucks man.

Kurt
 
Keep it simple :nice:

Get your gasket on and couple of bolts holding the header next to the head

Stick a small phillips screwdriver down several holes and mark it next to the
flange with a sharpie to see how deep the hole is ;)

Grady