Are you guys replacing the stock LS2 head bolts when you do a head swap? Is it absolutely necessary?

 

Yes get new head bolts. They are TTY

 

It's a mattter of preference. Some use factory head bolts while others would rather use ARP head bolts. Just keep in mind that factory head bolts are torque to yield. They are a one time use - while ARP bolts are not. Either way - just clean out the threads in the block real good(11mm x2 tap) as the factory bolts leave a lot of crud which can throw off your torque readings. Oh, and get all the water(moisture) out of the bolt holes in the block. This is a must.

 

Thanks for the info guys, I was unaware these were TTY. I'm picking up my heads this afternoon and will now plan on purchasing some ARP fasteners for the swap.

 

Update!
Here is photo of a FelPro gasket on top of the dealer gasket.
The FelPro covers the block and head, the "extra" of the dealer gasket does not appear to have any function.
Do I have an incorrect dealer gasket?

 

Neither one of these gaskets are the correct head gasket for an LS engine.

 

It is necessary. Either a new set of GM torque to yield bolts or ARP bolts or studs. I would go with ARP. The studs if you don't mind the cost.

A few extremely important things to know and do before you install. You need to CLEAN, CLEAN, CLEAN, CLEAN all the head bolt holds in the block. You need to remove every last bit of oil and/or coolant from every single bolt hole. I have used long Q-tips to get any liquid out; I saturate it and then use a new one until it comes back out dry. Then you want to chase the threads with either a modified old head bolt (use a dremel to cut 3 or 4 slots up and down the bolt on the threads or there is an LS head bolt tap set). Finally, I then use cans of compressed air with the thin tube on the end, place the tube at the bottom of the hole and blow out any debris. I will usually then put another Q-tip into each bolt hole to verify they are clear.

The bolt hole threads need to be clean and have nothing in them. This is to achieve the proper clamping pressure when you torque them. If there is any liquid in the holes and you try to torque the bolts, there is a good chance you will crack the block.

The other thing is to make sure both the block surface and head surfaces are cleaned of any old head gasket material. The safest thing to use is a plastic scraper so as not to possibly gouge the surface. If you are very careful, you can use a sharp utility knife blade but you need to be extremely careful.

Again, clean, clean, clean.

 

never run a tap into the bolt holes. you will remove stock with a tap. either use a modified bolt or a thread chasing tool

 

Yes, a thread chasing tool is what I meant.

 

Run OEM MLS gaskets. No reason to run anything else.

 

Agreed with one minor exception. If one wants a slight bump in compression, they could opt for a Cometic MLS gasket with a compressed thickness of .040 versus the OE .051

 

Indeed. Using the Cometic 0.040 gasket will give a tighter quench but still be safe and a bump from 10.7 to 11.0 compression ratio.

I am thinking I may do this in the spring along with sending my heads out to either Texas Speed or Advanced Induction for CNC porting. Would be a nice improvement.

 

Would CNC porting be justified on a stock engine?
Curious as to cost...
Any leads in Southern California?

 

AHP and WCCH are in So Cal and do CNC work...

 

I asked this question once:
https://www.corvetteforum.com/forums...re-torque.html
John Z said No, good enough for me.

 

I used ARP studs on my LS2, very happy with the results