Saab Link Forums banner

ARP Head stud pn?

2.9K views 22 replies 11 participants last post by  Green9kAERO  
#1 ·
What is the part number for ARP head studs? Is it the same for all of our engines?
 
#7 ·
You know why I quit using the straight shank bolts? ;) Anyway good luck.. The Pinto is a Iron head motor. Not as much thermal expansion. The undercut studs are needed for the Alu heads. Maybe not for a while but you will have some issues. This application has been discussed with a couple engineers at ARP.
 
#10 ·
We had some "issues" with the non undercut studs after many miles and after working with the engineers at ARP and a few other sources we cam to the conclusion that the undercut would be better. They have been in my vig for many warmup cycles and no issues along with many other cars.. But its not my problem. ;)
 
#17 ·
Looking to replace the head gasket on my 95 Aero, and have been looking at these threads. If there's problems with the straight ARP studs, wouldn't the same problem exist with the factory head bolts, since they are also straight walled .......... Anyone else thinking along these lines ? Is anyone running the Pinto studs, and if so, how are they holding up ?
 
#21 ·
The engineers we worked with at arp for both my car and Eds had lots to say about it.

in short:
The undercut studs make them more elastic.
Aluminum head on Iron block has considerably different expansion rates than Iron head.
Without the elastic help of the studs you have great changes in preload, this generally showing up in overload in the head gasket and pulling the bolts into the head.
This all is magnified by the number of heat/cool cycles. Road cars have more of this than say a racecar that only goes out a couple weekends a month.