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Kirkham Motorsports

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Old 07-16-2004, 09:37 PM
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Default 351W stock rods strong enough?

Hey guys, I was counting on using the stock rods in my 351W build (shooting for ~350hp). I was recently talking to a coworker about it though, and he said the rods were the weak link on these motors, and that he would at minimum have them shotpeened, and probably consider replacing them for even moderate horsepower. What do you guys think? This guy knows his stuff and I trust him a fair bit, so I was just wondering....

(relevant info: 351W, minimum overbore, keeping stock crank, shooting for mostly-reliable, modest power only)
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Old 07-16-2004, 11:09 PM
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This may not be a big help, but I ran a 351w in a ski boat for YEARS with stock internals without any kind of failure. That's running 5,500 RPM towing skiers for hours on end. I have no idea what kind of power I was making, but it was definitely reliable!

Tom
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Old 07-16-2004, 11:09 PM
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The stock rods will be fine at that power level. If you want put ARP rod bolts in them. 350 hp won't hurt them.
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Old 07-17-2004, 12:23 AM
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The OEM 351 rods used in truck application are the best if you are going to use factory rods. The area under the heads of the rod bolts are spot faced instead of being broached and are therfore less prone to failure in that area, because a stress riser is not created near the head of the bolts.

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Old 07-17-2004, 06:50 AM
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Dan;

Stock rods will be fine.... I would suggest you have ARP rod bolts installed and have them resized........My stock rods in my 350 hp 351-W are all still connected to the cranksahft on one end and the pistons on the other end.......22,000+ miles,40 or more drag strip passes shifting at 5500 to 6000 rpms,300 miles or more on road race track running from 3000 to 5500 rpms for 20 minutes at a time and no failure-no probelms........

For your application and intended use,stock rods will be fine...............

David
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Old 07-17-2004, 07:15 AM
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Alright, so if I used decent ARP bolts, the stockers will be fine? No need to even have them shot-peened or anything?
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Old 07-17-2004, 11:19 AM
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Dan;

Shot-peening will not hurt anything,not sure what it cost,but if it is reasonable,I would do it.......Anytime you change your rod bolts,you should have the big ends resized.......

The old rod bolts have ????? miles on them,ARP rod bolts are "heavy duty" type rod bolts and will give you a little extra insurance.......

David
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Old 07-17-2004, 11:22 AM
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David,

Thanks - what exactly is meant by having the "big ends" resized?

The old rods/bolts are the original factory ones from the car, 140k miles on them. I'll definitely buy some decent ARP bolts (was planning on buying good main/rod/head bolts anyway, seems silly to spend $3k on an engine and cheap out on $50 bolts).

Thanks
Dan
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Old 07-17-2004, 11:28 AM
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Dan;

The rod bolts are pressed in and what the machine shop will do is put the rod cap end on a sander and slightly sand the end down to get it perfectly flat,then they bolt the cap on the rod to specs and check the bore diameter...... It will be a little "small",then they put the rod end on a fixture and it is similar to honing a cylinder bore,they hone the inside to get it back to factory specs.......I can't remember what I was charged for this,it has been almost 10 years now,but not that expensive and very worth while......money well spent........

David
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