ARP Main stud kit

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douglas340

douglas340

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Hi, I've got an inquiry about the ARP main stud kit I'm installing in my 340. The stud in the rear cap doesn't sit down enough to allow the oil pump to bolt down(first pic). The kit also has two different types of nuts( second pic).....do I use these nuts without a washer and trim down the stud?.....is this what these nuts are for?
Cheers Doug

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I ground my high volume oil pump housing, to clear ...There are better ways. ARP knows of this multiple times ,and does not listen . Be patient, and wait for a better response. (I was not happy about my work . Overseas ,would be an , expensive to build a new short block due to oil pump failing.
B.T.W.: I highly recommend Mopar Performance .....
Mopar Performance Oil Pump Driveshaft and Distributor Gear Sets P3690715
Make it one and done time ,Mopar brother.
 
Abodybomber said:
I ground my high volume oil pump housing, to clear ...There are better ways. ARP knows of this multiple times ,and does not listen . Be patient, and wait for a better response. (I was not happy about my work . Overseas ,would be an , expensive to build a new short block due to oil pump failing.
B.T.W.: I highly recommend Mopar Performance .....
Mopar Performance Oil Pump Driveshaft and Distributor Gear Sets P3690715
Make it one and done time ,Mopar brother.
Click to expand...
I had to cut the rear studs off to clear my girdle on my 440/505, no big deal, just leave at least 1 thread thread thru the nut .
 
The stud/nut in the second photo does not require a washer. I just ground the stud and used that nut. Just make sure you don't grind the stud to much. You want to have 100% thread engagement with the nut. Also as previously posted, use a high quality hardened oil pump drive. I use either Mopar Performance of Melling. 65'
 
Known problem with the ARP stud kit. I used the stock bolt there and had the block line honed.
 
I had this exact issue when I built my 340. I don't think the nuts will clear the oil pump even if the studs are trimmed down, at least the 12 point nuts did not clear the pump on my engine.

I contacted ARP and they sent me a pair of bolts for the rear cap.

I wasn't happy with that solution so I requested a pair of shorter studs, and had the surface where the washer and nut sits on the cap milled down to just enough to fit the stud, nut and washer between the cap and the oil pump, making sure 1.5 threads of the stud are sticking up past the nut when fully torqued.

I had an Aerospace Engineer at work look at the cap and tell me if there was any strength compromised in the cap by milling that surface down slightly. His answer was no. He did suggest retaining the washer under the 12 point nut though.

A bit of extra hassle, but I've got the full benefit of studs on all mains.
 
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You have 2 choices; grind stud down for clearance, OR, use stock bolt in that location..........take your pick, eather one works.
 
I use the 12pt nut and cut the stud down. I've also had an instance where the pump body also needed a little smoothing to get some airspace in there even with the 12pt nut and stud cut so it's a "check - clearance-check-clearance" deal until you've got what you need. No sweat.
 
I have milled the oil pump and milled the cap down, and cut the stud down for clearence
 
dano said:
Known problem with the ARP stud kit. I used the stock bolt there and had the block line honed.
Click to expand...

Yep, been this way for years. On my 408 I used a factory bolt there, on the 434 I cut down a stud and clearanced the pump. As Dano posted, have the block line honed with the studs.
 
My machine shop laughed at the arp mains for a small block mopar. I have arp head, rod, clutch, and flywheel.
410 stroker - going on 4th drag season.
They ain't gonna do nothin but give you a warm fuzzy fealing...
 
LOL You ain't done grindin eather. Likely you'll be grindin on the oil pump to get the oil pan on.
 
j par said:
LOL You ain't done grindin eather. Likely you'll be grindin on the oil pump to get the oil pan on.
Click to expand...

And drill out the factory windage tray mounting holes to fit the small studs, then cut and bend the tray to fit the pickup......then get smart and buy a Kevko pan and find out their sump is over 1/2" off the bottom of the pan so cut and extend the pickup.....then....
 
j par said:
My machine shop laughed at the arp mains for a small block mopar. I have arp head, rod, clutch, and flywheel.
410 stroker - going on 4th drag season.
They ain't gonna do nothin but give you a warm fuzzy fealing...
Click to expand...

Your machine shop laughed at studs with higher tensile strength vs. oem bolts that have been stretched and heated multiple times... did they explain?

Douglas, I trimmed 7/16” off my stud and ran a die through to clean the threads, also used a thin washer. You could also use a flange nut of similar tensile strength.
 
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