ARP Head bolts too long

[GN HEAD]

I searched and couldn't find any info on the head bolt kit from ARP #123-3703, purchased from a very reputable vendor....says for 85-87 GN. My problem is that the center two bolts (the longest ones) are too long. They measure 4.5" from the top of the cap to the end of the bolt, and bottom out before the washer is close to the head. I doubled up the washers on those two bolts and it still doesn't feel right, like I'm up against the bolt shoulder and not clamping (little more that finger tight). I had 6 thousandths taken off the head to true it up and I'm using a factory style gasket. Is stacking 3 or 4 washers on this the way to go???
Any help will be greatly appreciated.....Thank You in advance.

 

[Nick Micale]

Since the 1985 and 1986-7 GN's use different blocks and head fasteners of a different length I would suspect that the listing and/or the bolts are screwed up? The early blocks use shorter bolts/studs.

A few thou of the head/block will make no difference if the fastener is correct for the application.

I personally verify the proper length on any head before it is installed, as I have had and seen this happen too many times? Nothing will piss you off more than a wrong bolt or stud pulling threads out of the block when in the car.

There are times with aftermarket heads I have needed to use additional washers to achieve proper clamping force. Sometimes you cannot use a longer stud depending on the head and the type of rockers.

 

[GN HEAD]

Thanks for the reply Nick. What part number do you recommend using?

 

[GN HEAD]

I think I'll just do-over and go with a stud kit.

 

[buickGN3:16]

i just used a new set of arp pro series head bolts & they were fine. Dont remember part # though, the box is locked up tight in my buddys shop but when i get back to it i will post it if u like!?


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[GN HEAD]

That would be great.

 

[buickGN3:16]

Arp-123-3603, sorry for the delay.


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[RmvBfrFlght]

For the '77 - '85 blocks, head bolts:

6-point: ARP 123-3601
12-point: ARP 123-3701

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