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Ok I know with some aluminum heads they say to replace the head bolts when you remove the head to replace the gasket or have the head machined. Does Isuzu recommend this?

Just make sure the old bolts go back into the same hole they came out of & the bolts & holes are clean & dry, then dip the threads in motor oil, shake off & install, torque in sequence in 3 stages. If you have oil or water pooled in the bottom of the hole the torque reading will be off. Felpro seems to be the best aftermarket gasket. Check the torque on the rocker shafts & head bolts & re-set the valve lash within a few days.

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'78 Chevy LUV,1.9,4sp,headers,31's,SAS Dana 30,Dana 20,SOA rear w/Aussie Locker, rough body, bought new 12/4/78.
'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.

They say replace them. I did when I redid my head gasket years ago and mine is still going strong even though I run it hard on the freeway once in a while.

Several engine parts manufactures state that it is mandatory to replace the head bolts every time they are removed. Something about aluminum and steel having different expansion factors and since the bolts have already been stretched once they are prone to not stretch the same amount again thus making head gasket failure more risky. I have read on some head gasket packaging that "if you are not going to use new bolts don't attempt to use these gaskets!!!"
Seems to me it is not worth the risk? Every performance engine builder replaces the head bolts as a standard building practise.
BTW you recieved some really good information on the previous post, cleaning the bolt holes, lubrication, especially under the headbolt heads and on the threads.

I would not replace them. I can't see how stretching would make any difference considering that the bolts don't bottom out. The bolts themselves look like nothing would harm them.
I can see where the company making the gasket would want to cover their backside but that's not exactly an unbiased point of view.
I've read here that they aren't easy to find if they are even available. Anyone have a source and a price?

Getting back in and re-torquing after a few thousand miles matters more.

Bolts stretch when tightened. In most cases, they snap back when removed. But like a spring that has been overstreched. they may never be quite the same again. We pull a torque on bolts hoping even torque will yield the even clamping force a head gasket needs. That is more likely with new bolts never subjected to the strain of being stretched before. Me, I follow directions. New bolts are only a small part of the cost of a head gasket job.

Well I know from school that they say on a performance motor and certain other motors to replace them.I think I will because I think it is cheap insurance.I would rather put in new bolts than replace my motor! And knowing about head bolt stretch even adds to the replacement factor.I just wanted honest opinions from you guys and I sure got them!

I found hex head head bolts here in Phx at 'Copperstate Bolt and Nut'. A couple of years ago I had a stock head bolt strip out at the allen hex head and had to drill it out to get the engine head off the block. The new Copperstate bolt turned out to be 5/8" or 11/16" regular hex bolts but it is working just fine. A great replacement.

5/8'' = 16 mm