ARP part numbers for 4.1 291 block and 14 bolt GN1s ???

[turbonut85]

I hae searched for what seems like hours for the correct ARP part numbers for head bolts and head studs to bolt some 14 bolt Champion GN1s to a 4.1L 291 block...can anyone confirm the CORRECT part numbers for both sets?? Thanks in advance!! ---Keith

 

[ek02]

Champion says the stud kit is ARP 223-4204. These will work if your threads are countersunk like a 109 block. If they are not, you will need to buy 2 sets and mix them up to fit.I used some studs from ARP set 123-4001. The problem is, some of the studs will not go deep enough into the block to keep the nuts from bottoming on the studs. You could use 2 washers on the ARP 223-4204 studs if you had some extras. The head bolts Champion rcommends are ARP 223-3705. I have no idea if they will work on a 4.1 without bottoming out. My latest 4.1 had the threads countersunk on one bank and not the other from the factory.

 

[Sleeper]

FWIW
I am working on a 4.1 with Champion irons, and am also trying to figure out what studs to use.
I have been getting some info from the Tech dept at ARP, and have got some stud lengths for the different kit that are recommended for the Buick motors.
Hope this help for future reference.
223-4204 (8) 3.750”, (4) 4.250”, (4) 5.000”
223-3705 (8) 3.060”, (4) 3.250”, (4) 4.300”
123-4003 (8) 3.750”, (4) 4.250”, (4) 4.750”
123-4201 (8) 3.300” ,(4) 3.600”, (4) 4.250”

 

[turbonut85]

FWIW
I am working on a 4.1 with Champion irons, and am also trying to figure out what studs to use.
I have been getting some info from the Tech dept at ARP, and have got some stud lengths for the different kit that are recommended for the Buick motors.
Hope this help for future reference.
223-4204 (8) 3.750”, (4) 4.250”, (4) 5.000”
223-3705 (8) 3.060”, (4) 3.250”, (4) 4.300”
123-4003 (8) 3.750”, (4) 4.250”, (4) 4.750”
123-4201 (8) 3.300” ,(4) 3.600”, (4) 4.250”

Here are some numbers that I came up with:


Studs
123-4001 (8) 3.300, (4) 3.600, (4) 4.250

12 point bolts
123-3701 (8) 2.675, (4) 3.780, (4) 3.060

I went ahead and ordered the 123-4001 stud kit. I'll post up what I find...

---Keith

 

[turbonut85]

Just got the ARP 123-4001 head stud kit. All the head studs will work fine with the 14 bolt GN1 heads in a 3.8L hot air block, 4.1L production 291 or 484 block, or a stage 1 block...so long as the head bolt threads have not been recessed more than 1/4" into the block. They would be way too short for a 109 block for sure. The 4 shortest studs leave about 1/4" of threads remaining on the nut end with the block end bottomed out in the block. The center 4 studs have 3-4 threads protruding through the nut...which is plenty. This is the set I need for sure. I suppose, if a guy was insistent upon all 8 studs having the exact same number of threads sticking through the nuts on the top side...then the 4 shortest studs (the 4 on the exhaust side of the head) could stand to be about 1/4" shorter overall...but IMO it isn't necessary. If I could ever figure out how to post pics with this new format...I would post some pics of these stuck through a Champion 14 bolt GN1 head. HTH somebody in the future. ---Keith