4.1 block & Champion irons. ARP studs?

[Sleeper]

Trying to avoid some confusion
I have a 4.1 block with Champion iron heads and am looking for the proper ARP head studs.
I come up with:
ARP-123-4201
ARP-123-4203
ARP-123-4001
ARP-223-4203
What is the right one to use?
Thanks

 

[turbofabricator]

4001 or 4201 depending on which nuts you want to use. I.E. 12 pt. (4201) or hex nuts (4001) Just consider the block as a StageI '77-'85.

 

[Sleeper]

4001 or 4201 depending on which nuts you want to use. I.E. 12 pt. (4201) or hex nuts (4001) Just consider the block as a StageI '77-'85.

Thanks, appreciate it. Just curious about the 223-4203 ones. What is different about them?

 

[Sleeper]

FWIW
Stud lengths:
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]

ARP 123-4001 I just test fit this kit on my 14 bolt GN1 head and they will work fine for my 4.1L 291 block. HTH. ---Keith