Need a Professional Builders Opinion.

[9SECVSIX]

A friend is building a billet girdled 3.8 The block has been honed with a deck plate and ARP 170,000 psi head bolts, I would like to see him have more clamping power and have suggested APR 200,000 studs. He says now that the block has been finished with the bolts he can't switch the build to the studs.
I really don't see it being much of a problem..What's you .02 on the issue FWIW he will be using Fel-Pro 9441PT gaskets.
Thanks
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[m233roller]

The little bit of pulling difference between the bolts and studs isn't going to change anything that much ( if at all). I changed from head bolts to studs on my engine and I ran the hell out of it for 7 years with NO problems. I'd go with studs also as they'll give you around 10% more clamping force.

 

[84BuickGNYorkPA]

My thoughts are the threads in the block will be weaker then the ARP bolts/studs, so I doubt it would matter one way or the other. Take a scrap block/head sometime and crank on the ARP bolt/stud untill something strips, I would bet that when you inspect the carnage you will find the threads ripped right out of the block and the threads are still good on the bolt/stud.

Chuck

 

[turbofabricator]

My opinion is that the blocks cast iron threads will not yeild before the ARP studs start to yeild. (the stock head bolts are torque to yeild, remember) Going to the stronger studs shouldn't change the amount of torque applied, but the weaker stud will yeild under high cylinder pressures. If you torque the stronger stud at the same value, the cylinder wall distortion should be VERY minimal, if any. The head deck will warp if using an iron head, too. There is only about .22" of head deck between the inner head bolts on a 8445 casting. Years ago we use to install deck pins to hold that area of the deck better. (that was before the availability of injectors that flowed more than 30 lb./hr., but now with good injectors, we don't have to change head gaskets like most folks changed oil.) If using aluminum heads the head will still move a fair amount. I personally don't think the stronger stud will have an ill effect on anything, except the pocket book.