Originally Posted by 20/20 vision

with regards to std head bolts - these are difficult to get hold of. the proper bolts have "KK" on the heads whereas just about everything you see on ebay / burtons / etc is just a high tensile bolt which happens to be the correct size. you even see the wrong ones advertised (even by 'respcted' tuners) as 'genuine Reinz head bolts' which is true - but they are not genuine fitment on a YB.

if the ARP studs crack the block because of the differences in expansion (alum v steel bolt) then that same problem will likley occur with the use of the 'wrong' type of std head bolts.

the correct bolts are 'torque to yield' which means that you stretch them past thier elastic limit into the plastic region and permanently deform them. in the case of high tensile replacements you are stressing the block threads and (my opinion) is that this is a bigger problem if you use a metal head gasket which has no 'give' in it.

there are some bolts on ebay where an attempt has been made to mitigate the effects of this problem by machining the shaft of the bolt down so that the waisted section will stretch. no idea if this resolves the problem and the outfit who supplies them are unreliable anyway