Well, I decided to call ARP and see what they said, lol. They do not have hp ratings for their different metals. He said they leave it up to the end user to decide which ones to go with. I asked why should I go with a 2000 or L19 over an 8740 and he just said its really up to you and what you wanna do with the motor. wtf?

 

I think he should have said a few more things, but for the most part, he's right. Every application is different and one bolt does not fit all

 

The differences between the materials is explained on the ARP website under their "Techinal" category. Interesting read and should explain the info you're seeking. Too many intangibles to put specific horsepower figures on their products.

 

I would think piston/rod weight, stroke, rpm would be more of a factor than a HP rating. I look at it as a package since in the end it's only as good as the weakest link.

Gotta love some of the tech guys. I called Comp Cam about my combo and a cam I thought would be good. Guy said...." Uh yeah, that should work" I won't even get into my contacts with TCI.

 

I thought at one time i saw a chart, it may have been in eagles book with thier rod bolt selections and HP ratings. 6" H beam with the 8740 i thought was 750 HP and with 2000's it was 1100 hp or something.

 

Rod bolts load is largely dependent on stroke and reciprocating package vs RPM this is more of a factor than HP. So as an example a turbo motor of 526 inches making 3500hp will be a LOT easier on rod bolts than a 1000 inch Leonard motor making 2150hp due to the enormous FPM and package weight of the bigger motor.

That said look at it this way if a 900 inch motor with 4 hits can live with l-19 bolts a full on 275 motor would probably live with 8740. Now if you wanted to upgrade to 2000 that would be fine but to me the L-19 is overkill and also the L-19 is a tricky material that requires care to avoid hydrogen embrittlement due to exposure to chlorinated hydrocarbons and the like.

 

What you say is correct. It's the mass of rod and piston and the rpm the engine is being spun to that is going to determine the Rod Bolt required and its life span.

 

I prefer to never tell my rod bolts how much power I'm making.

 

Thanks guys I went ahead and got the 2000's.

 

Good choice!

 

Does arp sell a upgraded 2000 bolt in a 7/16 x 1.400 size? Wanting to replace the 8740 cap screws in my Scat Pro-Comp I beams

 

I believe so, since that is the bolt that comes in Callies compstar

 

Finally! Jegs swears up and down that arp doesnt sell that bolt. So ive never been able to get a part number or price

 

It might actually be 1.450 UHL

 

Here is the page from thier 2014 book for cap screw rod bolts.

 

I dont see a 1.400 even on the chart...And these current cap screws are 1.400, thats what they say in the book for these rods

 

ARP 3.5 and custom age 625 on that chart for Carillo rods are 1.400

 

best bet may be to call ARP direct and see what they say.

 

Ill give that a try tomorrow. Thanks!

 

Yep I need a 7/16...ive been side tracked lately, Im going to call arp in the morning. And will let you guys know what they say. Thanks for the replies so far

 

Any chance you got around to calling ARP? or if even you are still here? I was searching and this thread from 2014 arose.

 

Had always wondered how rod bolts were rated by by horsepower... instead of RPM, stroke and piston mass... as during the power stroke, the rod is under a compressive load, and the rod bolts are just along for the ride. Rod bolts are not under tension on the power stroke.

 

Probably ARP makes those 1.400" under head 2000 7/16" bolts under contract to the rod company and can't sell them to individuals. (Replacements for Eagle rods are done that way, as are Molnar.) Callies/Compstar has them listed as replacements for SBC small journal 6.000" rods. I have a set of those rods here and am going to order replacements during the rebuild, from Callies. The part number is on their site. These have an undercut between the threads and the head of the bolt.

 

Just call Scat and order some....
No need to reinvent the wheel, likely get them cheaper from them than ARP.

 

Just found this... Interview with ARP in regards to rod bolt choice.