At what point do we need to upgrade head studs and main studs?

[Amir Ghadiri]

Could anybody with first hand experience chime in on how much power the factory head studs and main studs can handle?

I'm currently building my motor and trying to determine if it's worth doing for the power goals I've got in mind.

Thanks for your input!!

[slicktop]

Originally Posted by Amir Ghadiri

Could anybody with first hand experience chime in on how much power the factory head studs and main studs can handle?

I'm currently building my motor and trying to determine if it's worth doing for the power goals I've got in mind.

Thanks for your input!!

Well considering people have done 500whp on the stock block for extended periods, I'd say that's around the safest currently explored. However, if you're rebuilding your engine either make sure your studs are within spec if you're reinstalling or buy new OEM studs.

That said, you should spend the extra money and upgrade considering it's pretty cheap for ARP fasteners.

[zkv476]

From building EJ motors, the head studs are more dependent on the boost you plan to run to prevent head lift, and the case bolts I'm not sure what the failure point was. The head studs are cheap enough to run just for insurance. I did read about the case bolts messing with the main journal oil clearances though because of the different torque specs. What's your power target?

[Amir Ghadiri]

Originally Posted by zkv476

From building EJ motors, the head studs are more dependent on the boost you plan to run to prevent head lift, and the case bolts I'm not sure what the failure point was. The head studs are cheap enough to run just for insurance. I did read about the case bolts messing with the main journal oil clearances though because of the different torque specs. What's your power target?

I'll be running 20psi on pump and possibly 27-28 on e85. I'm assuming power will be at approx 425-450 and 550-575 wheel, but I don't necessarily have a hp goal I need to meet.

I was thinking I'd just upgrade the head studs and keep factory case studs, and it sounds like that may be a good plan?

[zkv476]

You definitely want head studs for that level of boost. But yes that's a good plan. Unless you are building a car for time attack or majority track duty and harsh abuse you don't really need the case bolts. They require a decent bit of work alongside them, since they oval the main bearings if you just put them in.

[Amir Ghadiri]

Originally Posted by zkv476

You definitely want head studs for that level of boost. But yes that's a good plan. Unless you are building a car for time attack or majority track duty and harsh abuse you don't really need the case bolts. They require a decent bit of work alongside them, since they oval the main bearings if you just put them in.

Okay cool, thanks for your help!!