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Small block chevy bolt torque specs

483 Views 4 Replies 3 Participants Last post by  eric32
Hello guys I have a question and would like some opinions on a few things. I have just gotten my new small block chevy short block put together as of yesterday and I went over the notes the machine shop gave me and recommended torque specs to use on my connecting rod bolts along with my mains and head studs. All of my fasteners are ARP. I had them check the align bore hone and also asked for all the torque specs they used to check bearing clearances so I can make sure to use the exact same specs to make sure I have the same clamping force used from there end from top to bottom. I had them use studs as well for the torque plate hone.

Anyways to get to my point, the machine shop torqued my arp 7/16 connecting rod bolts with arp ultra lube to 60 ftlbs and got the clearances they were making for me with new bearings and stuff. ARP calls for 64 ftlbs for those bolts and the machine shop I brought my stuff too only builds high performance stuff and nothing of factory motors and I can say they did a heck of an awesome job on my block and everything else.

My question is I asked them about the torque specs and the machine shop guy who has more years of experience then I have been alive said he does not like to always like to go full torque value on the bolts with arp ultra lube as he says its so slippery that he has come across broken rod bolts before and does not like to use it personally at times but he said he used 60 ftlbs when checking my bearing clearances. He said to not go over that or the other specs they used and I will be fine.

They torqued my rod bolts to 60 ftlbs and mains at 70 on the big bolts and 40 on the 3/8 bolts. The head studs were done at 70 on the long and 65 on the short. They said to strictly follow those specs to match what they did for the work and clearances they did.

Using a known good torque wrench while checking there work and stuff my connecting rod bolts were torqued to 60 ftlbs like they did too keep the same clearances. ARP calls for 64 ftlbs on there bolts on my Scat I beam connecting rods that has the bigger 7/16 sized capscrew bolts. Will that lack of 4 ftlbs really make a difference? I torqued the mains and head studs to what they said to do which is slightly different then what ARP calls for.

I have done less then what ARP has recommended before in the past on the head studs by a little with no problem but never on the connecting rod bolts. Should I really sweat the 4 pounds? Thanks guys
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From my research on this issue many folks at least on small block chevy builds don't always like to torque the studs to the very high amount that arp calls for and goes a bit less and closer to what stock specs were at least on the mains and head studs when used and never had problems. I in the past have only went 70 instead of 80 ftlbs on my blocks regardless of being GM or Dart and never had a problem. I know ARP fasteners need some slight more torque to get proper clamping force but I don't think they have to be exactly the super high amount in order to be torqued correctly enough to do there job.

Some folks have had there threads ripped out with using the studs and torquing down to 80 ftlbs. Even someone called ARP and they even said they could go less and be fine especially if using aluminum heads vs iron. The connecting rods is my main worry with that last bit of 4 pounds. The mains are good and still need to get my head studs torqued down.
Yeah that is my plan is to just leave it at what they used in order to get the clearances and stuff for things being machined and the clearances they got with the said torque specs they used. I don't want to mess things up by changing stuff too much with higher torque and skew the clearances they had with the torque amount they used to get those clearances.

It won't be raced and put through the ringer and back and should be fine. Thanks to all who posted and helped.
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