If I change the headbolts but do not remove the heads is it necessary to replace the headgaskets? I am installing a set of ARP headbolts.

 

not at all

 

Just be very careful. If you get fluid in a bolt hole and don't realize it, you will either snap a bolt or possibly crack the block when torquing the new bolt in.

 

+999999999999

 

What i would suggest that i have seen done is people taking off the water pump hose and possibly thermostat housing and using a shop vac to suck out all of the coolant. This would help prevent any potential coolant from going into the bolt holes sine you wont be able to blow the holes out very well with the heads on the car. It would be worth the extra insurance for the $20 or so in coolant you'd be wasting.

Just curious, why are you replacing the head bolts?

 

A word of warning. The factory head bolts have a thread locker that is very hard. You need to clean this out to get the proper torque applied to the fastener.

Cleaning these holes is one of the most tedious steps and the biggest PITA of the whole process. I don't know how you can clean the bolt holes adequately with the heads still on. JMHO.

 

Yeah i have heard the best way to clean the bolt holes is to take an hold head bolt and cut a groove down opposite sides of the threads to act as a 'tapping' bolt. The grooves will give the debris somewhere to go to when it gets re-threaded into the hole. Then you just blow the holes out.

 

ARP sells thread chasers for the LS1. I used them on my head swap and they worked great.

Big bolts - M11 x 2.00: part # 912-0011
Small bolts - M8 x 1.25: part # 912-0001

 

now that i think about it. you might as well pull the heads all the way off if youre gonna do this. might as well replace the gaskets too.

 

I am going to be boosted. I know studs would of been better, but I bought these before the procharger so I figured I would use them. I wanting to run about 8psi.

 

boost its not as violent as spray, only 8psi the bolts should be fine, but they are correct, you will need to chase the threads, and that will be harder with the heads on the car for sure.

 

ARP head bolts will be more than sufficient for your application, don't sweat it.

 

Thx for the advice guys

 

Again, just be very very careful when re-installing the new bolts. Hand tighten them without a ratchet and if you hit any tough spots before the bolt head his the cylinder head, stop, and back that bolt out and rerun a chaser through it. There is no worse feeling when working on a car then have a bolt strip, snap, or split the hole it's going into.