Stud length GN1

[Martin U]

While swapping out my ARP bolts for studs I noticed that the longer studs in center came up a tad short on my gn1's. This was with the studs finger tight,just starting to bottom. with washer and nut i could use about 3/16 more length to get 100% bearing in nut. The stud length is 5.0 in. Part #223-4204.
?-Do they NEED to bottom out in the block?
I'm thinking I'll just bring the heads into the shop and spot a bit deeper. I also am not to happy with the spot face dia,it could be a slightly larger dia. Tommorow I will check the dia.
?- Any one know how much meat is under the head?
? can I order 4-5.25 long studs from ARP?
Mart

 

[49-blues]

ARP makes studs to properly fit the GN-1 heads. go to their website.

 

[Martin U]

The part # listed in my first post IS the same one listed. It is from thier site. and yes I have the correct pieces.

 

[Otto J]

I may hae some at home,Ill double check
What length do you want them?

 

[Martin U]

I found this posted by Cal Hartline in another site,
"3) The head bolt surface to the block is .120 longer than stock heads.
This means that if you screw studs in until they bottom out they will
be too short on the upper center two. You don't need to buy longer
bolts, just don't screw them in quite as far. They will still have
around .510 of thread engagement. This is more then is necessary with
the 7/16 head bolts that these cars use. When you put the studs in all
the way, all you are doing is screwing them further into the water
jackets."

That is exacctly what I found. I didnt like what I had found on mine. This was AFTER reading all the instructions and post saying "finger tight" ect..
I guess a note should be said to anyone else that tries to do this,that doing it this way on the two center studs will result in the nut NOT having enough thread engagement. Someone might just miss this.
I like to see 1.5 X dia on most threads. +.437X1.5=.6555 depth.
Maybe we can get ARP to change to 5.25 studs for the center locations so they can bottom on something,not move during the torque sequence and no more issue for anyone?

Otto IF you have 4 studs at 51/4 in in length I'll take them off your hands. Send me a price and we will work it out.
I hope this helps someone else.