So recently I've been reading that the ARP 3/8" headstuds for our cars will eventually give out under higher boost, and the best thing to do is to drill and tap the block for larger 1/2" studs. I've tried searching on the subject but came up with nothing yet. Can someone shed some light please?

http://www.2gnt.com/index.php?d=1/2%20inch%20ARP%20headstuds

There is the wiki article Mikey wrote up with part numbers and some info.

I know Hahn used 1/2" headstuds, and have *heard* that 22psi+ will lift the head. Take with a grain of salt, because I have never seen evidence of this.

But, if your going for a reliable high boost build, I would probably go with 1/2" studs for extra insurance.

as soon as I do this in about a month, I plan on adding pics to enhance it. Before/after type pics, and exactly what I've bought.

Originally posted by teklein
http://www.2gnt.com/index.php?d=1/2%20inch%20ARP%20headstuds

Thanks man, thats exactly what I was looking for!

Originally posted by 420agreenvilleSC
as soon as I do this in about a month, I plan on adding pics to enhance it. Before/after type pics, and exactly what I've bought.

Sounds good and that would help out alot.

This is all just he said she said rumors.

No one has actually prooved this theory yet.

hahn's RS had head lift problems from exessive pressures. After the upgrade, the problem went away. Of course, nobody has proved it other than hahn, and it may only benefit people that boost high daily, but nevertheless, it is good insurance if high numbers are in the engine's future.

Im running 23psi on 3/8th studs with no problems. Approx 350whp. I plan on running these till the head lifts then replacing them so maybe we can get some better info on when the head starts to lift.

Some pics of the process would be awesome.

Really curious in this mod... Please post pics and all the info you can about it. What parts did you use and all that stuff and what other things did you have to mod. Also prices I am going to buy the arp head studs soon want to know if it's worth it or will the 1/2" mod will be better.

Keep in mind that your block needs to be retapped and the head redrilled for this.

Just wanted to throw that out there...

I run 22psi daily and I have done 30 PSI on occasion......factory studs. If i recall the Hahn motor from the RS was sold with 3/8 studs.

The hahn motor from the RS, apparently is still owned by hahn. They haven't sold it yet. Perhaps they had more than one motor. Nevertheless, i'm sooooo contemplating NOT putting in 1/2'ers. Its just something that I keep thinking, "...do i REALLY need to buy new studs, pay a shop to retap and bore out the cylinder head stud paths?". I mean, really, is it necessary if you'd like to hit 25psi. I just don't EVER want head lift to be a problem.

I guess saying that, i should just stop being a pussy and do it while I can... I hate money. FUCK

Originally posted by 420agreenvilleSC
The hahn motor from the RS, apparently is still owned by hahn. They haven't sold it yet. Perhaps they had more than one motor. Nevertheless, i'm sooooo contemplating NOT putting in 1/2'ers. Its just something that I keep thinking, "...do i REALLY need to buy new studs, pay a shop to retap and bore out the cylinder head stud paths?". I mean, really, is it necessary if you'd like to hit 25psi. I just don't EVER want head lift to be a problem. I guess saying that, i should just stop being a pussy and do it while I can... I hate money. FUCK

Downpipe! We had this convo last night :P

If you were gonna go for hardcore crazy boost numbers, then go 1/2", but your setup would benefit from a good downpipe more than anything :)

Yeah the more I here about the 1/2" stud upgrade, the more I lean towards staying with the arp 3/8" studs. The most boost my motor will see is probably 26psi or so. Looking just to get 350whp and be done with it.

It's really only meant for engines that see 25+psi DAILY. Even though its meant for that purpose, terry is right, it hasn't been PROVEN that you actually NEEEED 1/2", so, right now, my mind is staying on the 3/8 studs due to $$ and I don't think i'll ever go 25+ daily.

Originally posted by 420agreenvilleSC
It's really only meant for engines that see 25+psi DAILY. Even though its meant for that purpose, terry is right, it hasn't been PROVEN that you actually NEEEED 1/2", so, right now, my mind is staying on the 3/8 studs due to $$ and I don't think i'll ever go 25+ daily.

I have been saying this in every thread for the passed 6 months. It has yet to be actually proven, its all he said BS.

Why not be a guineau pig...to do the studs anyway, you have to pull the head...might as well just run your 3/8 studs and then if it happens, you atleast have a reason to pull it and do it.

I built my newest motor to handle power, if I thought I would have needed the 1/2 studs, dont you think I would have done it?

Originally posted by eclipse982nrRST I built my newest motor to handle power, if I thought I would have needed the 1/2 studs, dont you think I would have done it?

good point.