Fox ARP Main Studs or ARP Main Bolts for Stock Rebuild

bleedinggreen · Sep 12, 2020

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.

LILCBRA · Sep 12, 2020

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.

CarMichael Angelo · Sep 13, 2020

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.

bleedinggreen · Sep 13, 2020

Thank you for the info guys.

Follow up question for you, if I went with stock replacement main bolts, instead of ARPs, would it still need an align hone?

HemiRick · Sep 13, 2020

New main bolts of either kind will NOT require an align bore, only studs will.

General karthief · Sep 13, 2020

Is it going to the machine shop for work? If yes, get it line bored.

bleedinggreen · Sep 14, 2020

General karthief said:
Is it going to the machine shop for work? If yes, get it line bored.

Yes, I'll be taking it back to the machine shop. Already had it in for a few things, but I didn't realize that I had to replace the fasteners or that it would require additional machine work. I'll just chalk it up to a learning experience.

revhead347 · Sep 14, 2020

CarMichael Angelo said:
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 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

foxbodybill89 · Sep 17, 2020

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.

revhead347 · Sep 17, 2020

foxbodybill89 said:
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

Fox ARP Main Studs or ARP Main Bolts for Stock Rebuild

bleedinggreen

LILCBRA

I wish I didn't have all of these balls in the air

CarMichael Angelo

my rearend will smell so minty fresh,

bleedinggreen

HemiRick

I'd be looking at jacking under the house

General karthief

wonder how much it would cost to ship you a pair

bleedinggreen

revhead347

Apparently my ex-husband made that mistake.

foxbodybill89

Active Member

revhead347

Apparently my ex-husband made that mistake.

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Fox ARP Main Studs or ARP Main Bolts for Stock Rebuild

I wish I didn't have all of these balls in the air

my rearend will smell so minty fresh,

I'd be looking at jacking under the house

wonder how much it would cost to ship you a pair

Apparently my ex-husband made that mistake.

Active Member

Apparently my ex-husband made that mistake.

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