So how much WHP does a stock block evo 8 hold without a set of ARP Headstuds?

 

I was pushing 420 for a year.and then I put arp studs.cheap insurance.some ppl pushing even more but why wait untill you blow gasket?

 

basic arp head studs are only 90 bucks why risk anything

 

There's a couple threads on this topic bro... plenty of info/debate

 

How difficult are these to install? Knowing you will not use the 1x1 method and replace the HG?

 

Interested in this myself. Just went to a HTA73 Green and now it shows i'm making around 460/400 at 27psi on E85.

I think it's about time to get in and do cams, springs, and headstuds.

 

Boostin performance replaced 1x1.it's all about money brothers.$120 job vs $500(head off).

 

Better to change them with head work

 

My 8 makes 525/402 on a stock block/stock head studs, and I don't have any issues. Obviously, a good tune is needed to keep you from blowing your HG.

 

Its all about the tune. I made 574/399 on stock everything other than the turbo kit obviously. I have seen cases of WG failure, spikes to 40+psi, and the rods break before the headgasket blows.

 

Yup, I guess it's in the tunning and obviously keeping torqe in the low 400's

 

Spend the money and put them in. Do it right the first time. It'll save you in the long run.

 

stock head studs are far better than most think. I set out to test how good they are in my own personal car many years ago. I wanted to know when it was a good idea to install stronger studs. on the dyno I got up to 511tq with no gasket sealing issues. I would have tested higher but other issues with car prevented more pulls.

I would say that 99.9% of head gasket failures are due to detonation flexing the head. notice I didnt use the word head lifting. head lifting would suggest the studs are stretching and allowing the head to lift. this I think never really happens. I have seen a couple hundred blown head gaskets. they all blow at the center points between the studs. NEVER near a stud. if studs stretched like people suggest wouldnt the head remain straight relieving tension on the gasket everywhere around the bore? so why do you never see gasket blow anywhere else but farthest from studs? because the head flexes. its got nothing to do with studs. POOR TUNING is the cause of blown head gaskets. you cant stop head flex with better studs. head flex is a result of detonation.

and heres the real kicker. bigger badder stronger studs cause head distortion. I.E. head flex. there is a reason the early 4g63 used 12mm studs and later cars used 11mm studs. when there is extreme cylinder pressure you want the studs to stretch a little. if they dont the head will reach head flex sooner. its easier to blow gasket with head flex than with head lift. head lifting will put equal pressure at all points on gasket, head flex will put less pressure on the areas where you always see gasket blow.

so when are better studs needed? when you have both head lift and flex. in which case you will reduce how bad the head gasket blows. only way to stop head flex is with a properly tuned engine. and realistic power goals. running 40psi on 11/1 engines you have no chance of keeping head flat no matter how good the tune is. you are simply pushing parts past design limits.

 

anyone who thinks a 1 by 1 replacement of studs is a bad idea doesnt have much knowledge on how an engine works. you dont need to take head off to replace studs. have you ever read a factory service manual on how to re-torque your head studs? its doesnt hurt gasket seal in any way to loosen studs then torque them back up. when an engine runs its is expanding and contracting. and parts are flexing and moving around. the head gasket is more dynamic than it is static. meaning there is movement between head and block. gasket has to flex during this movement. thats why metal gaskets are made in multiple layers. the top and bottom stick to head and block. the middles layers allow for sliding movement. there is way more stress on gasket when engine is running then there is when you loosen studs to re-torque them.

 

Since switching to e85 I have been worried about popping my hg. At some tracks I sustain 32psi in fifth gear for a long time!!! I cant believe the stock hardware can take it but it does.... lap after lap event after event. Im at 430whp (mustang dyno). I dont plan fix something that's not broke.