Well, it looks like that 68 400 I finished the mechanical restore on in January blew a head gasket. Water is coming into at least one cylinder.

I checked the head bolt torques and they were all loose by about 1/2 to one flat. It has been suggested by a buddie of mine that the old head bolts might have stretched. Has anybody had this happen to them? I've always reused head bolts on all my Chevy motors in the past and never had a problem.

The machine shop said the block didn't need decking when I rebuilt it, so I would assume they are flat. Heads were milled.

If I need new bolts, where can I get them? Ames' bolts don't have the studs on them.

They shouldn't have stretched. Bolts that stretch are known as "torque to yield" and are usually a one time use. I like torqing bolts down in 2 or 3 steps to get to the final value. Did you torque them to final value all in one step? What kind of head gasket set did you use?

ARP should have the bolts. In the automotive repair field, if
I sold a head gasket job it would ALWAYS go back together with new bolts. It's good insurance. I'm no going to say I know everything about bolts stretching, but I'm sure they have to stretch some.

I wish you had posted this a few days ago... I just sold a set of 68 head bolts for $30. You can find them sometimes on epay

Said you had heads milled.
I havent experienced, but did you make sure the bolts wernt bottom'g out?

I believe I had more than enough threads left after the mill. Can't remember the exact amount.

Yes, I torqued them in 3 steps. I used the blue FelPro gaskets.

This is a new one to me and iIve been builing cars over 30 year. Part of that time was for a mass volume "production" machine shop. Normaly unless the bolts are damaged or it is a very high performance application re-using head bolts is acceptable. Did you install the heads yourself or have them done and are you sure that they were torqued to spec? Were the bolts properly LIGHTLY oiled for installation or installed dry? Dry installation can give a false torque reading that could possibly cause this. Lastly-what type torque wrench did you use, and if it is not yours where did you obtain it? "Clicker" type wrenches are easily knocked out of calibration if dropped or abused. If they are turned down below the minimum measured setting it will throw them off and possibly damage them. I am sure rental/loan-a-tool places seldom if ever check calibration. By international standard these wrenches are allowed +/- 4% to 6% at calibration. If a "Beam" style wrench or Digital wrench was used there should be no problem. Just trying to help GOOD LUCK

I can't remember for sure if I lubed them or not. I didn't use sealer because of the blind holes. I thought about the consequences of dry threads today, but couldn't decide if it would make much difference. If they were installed dry, something made them slippery now since I was able to get a little more torque on them.

I used my Craftsman clicker torque wrench. I always set it to zero when storing like I was taught in the USAF. I had the cal lab at work calibrate it several years ago.

Unless they've changed in the last year or so, the ARP head bolts do not have the studs either.

OK, here are the results of removing the suspect head. There is a pit that runs right underneath the sealing surface/metal ring of the head gasket. There's my leak! I drew the two red lines to show the owner where the metal ring on the gasket is located.

The machine shop is going to repair it free of charge. He said he will use a nickel rod to fill in the holes and remill them.

I checked the plugs on the pass side and they were all perfect! I'm going to forget about the bolt stretch issue as I think it's non-existent, at least in my case.

The machine shop did mention that a reduction in torque is normal, although I thought the modern gaskets today don't need retorquing. I might try to partially remove the engine so I can get at the bolts. There is no room next to the AC box.

Dang! You must have one nice camera to get a shot like that!

Still a concern cause that wont cause bolts to come loose.

Nah, just a regular Canon set at the macro setting.


The machine shop said that is typical. I really don't know what the torque was on the bolts when I checked them.

After several engine rebuilds over the years, I have never gone back to retorque the bolts, so I don't know how "normal" this is.

Now, I'm starting to doubt myself. What if I didn't torque them to 95 lbs-ft? I sure don't remember that specific number, so who knows?