Fox ARP Main Studs or ARP Main Bolts for Stock Rebuild

bleedinggreen

5 Year Member
Aug 13, 2018
31
7
18
Humble, TX
Me and my son are currently working on rebuilding the engine from our 89 LX. I was reading that it's a good idea to replace the main and rod bolts while you have the bottom end apart, so I planned on replacing the stock fasteners with ARP fasteners and then having the rods and mains align honed. I'm just wondering if it's worth the extra $15 to use studs instead of bolts on a stock engine.
 
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One thing to think about as far as that goes:
if you have studs installed on the rods, you'll want to be sure to use a piece of fuel hose or something on the studs to protect the crank while you're reassembling the engine. I dunno when they changed and went to bolts vs studs, but that was considered standard practice for the older engines. Otherwise I think it would boil down to personal preference in this case.
 
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In a stock block there’ll be no benefit to using a main stud as opposed to a bolt. The block itself is the weak link above a certain power level, and it all fails above the fastener anyways. And as you’ve stated in your plans, in some cases using studs requires that the main bore be honed, as the studs can change the roundness of the hole. New rod bolts always require a rod resizing for the same reasons. And regardless of whether or not the bolts are old or new,...putting some sort of protection on the bolts to keep them from nicking the crank is a good idea.
 
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In a stock block there’ll be no benefit to using a main stud as opposed to a bolt. The block itself is the weak link above a certain power level, and it all fails above the fastener anyways. And as you’ve stated in your plans, in some cases using studs requires that the main bore be honed, as the studs can change the roundness of the hole. New rod bolts always require a rod resizing for the same reasons. And regardless of whether or not the bolts are old or new,...putting some sort of protection on the bolts to keep them from nicking the crank is a good idea.

Yes :leghump: there is. Studs are always easier to install than bolts. Worth the $15 in my book right there. Studs build confidence in the assembly process. But yeah, there is no strength reason to do them. All my engines have factory main bolts.

Kurt
 
Personal preference, I would always fully machine any engine that's apart for a rebuild, might as well get it arrow straight and build it right. Also like the use of studs when possible, they make assembly easier and also torque more accurately than bolts.
 
Personal preference, I would always fully machine any engine that's apart for a rebuild, might as well get it arrow straight and build it right. Also like the use of studs when possible, they make assembly easier and also torque more accurately than bolts.

That manuever could cost you 12 months though. Machine shops are notoriously bad on turn around time.

Kurt