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post #1 of 11 (permalink) Old 07-15-2012, 09:26 AM Thread Starter
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Rod Bolt modifications - 3/8 for 289

Based on the fact that stock 289 rods use 5/16" rod bolts, has anyone considered tapping the main body of the rod for 3/8 - 24NF cap screws? The idea would be to have the stronger bolt and add clearance where the head would have been if using a conventional rod bolt. I see that the drill size is Q, 0.332", so there should be enough material there to accommodate the tap for good thread depth. Thinking this might be a good way to save some money over aftermarket rods.
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post #2 of 11 (permalink) Old 07-15-2012, 09:30 AM
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Re: Rod Bolt modifications - 3/8 for 289

Just use ARP bolts. John--Las Vegas
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post #3 of 11 (permalink) Old 07-15-2012, 09:46 AM
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Re: Rod Bolt modifications - 3/8 for 289

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Originally Posted by hd_cat View Post
Based on the fact that stock 289 rods use 5/16" rod bolts, has anyone considered tapping the main body of the rod for 3/8 - 24NF cap screws? The idea would be to have the stronger bolt and add clearance where the head would have been if using a conventional rod bolt. I see that the drill size is Q, 0.332", so there should be enough material there to accommodate the tap for good thread depth. Thinking this might be a good way to save some money over aftermarket rods.
SAVE MONEY !!!
you able to perform all the work ?

includes the right class of thread , offset boring the bolt holes , resize the big end ?

get a spare/srap rod a give it a go
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post #4 of 11 (permalink) Old 07-15-2012, 12:28 PM
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Re: Rod Bolt modifications - 3/8 for 289

BAD idea. Back 30 years ago before GOOD bolts were available, some would replace the stock 5/16" bolts with 11/32" units from small journal chevies. However, even that was questionable, as boring out for the new bolts weakened the rod more than the larger bolts helped... so it meant people went backwards.

Nowadays, with good pieces from ARP, there is no need to try and roll the dice with a larger bolt. I used 5/16" ARP pieces in a set of 289 rods to run mid 10 second 1/4 miles with a 200hp shot of nitrous, shifting at 6800 rpm. I ran that engine for YEARS... HARD and OFTEN... with zero problems with the rods.

Do NOT use larger diameter rod bolts. You're weakening the rod, and nowadays, better alternatives are available.

Just make sure you have the rods resized by a REPUTABLE shop any time stronger rod bolts are installed... as the different clamping force will pull the big ends out of round. You're dealing with small clearances, and it doesn't take much to throw it out of spec.

Good Luck!
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post #5 of 11 (permalink) Old 07-18-2012, 08:32 PM
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Re: Rod Bolt modifications - 3/8 for 289

Makes no sense to me to pay someone to resize the rods after installing bolts, when a set of 8 STEEL rods with 3/8" cap screws is a couple bucks more....and that way you get a better rod, better bolt, better all around.

I just saw on Summit where the 289 Pro Stock Scat rods have gone up. Last time I looked, they were $211 + ship. Now $273. Might be cheaper if you look around. But those are some GOOD rods. Nowhere near, say, Oliver or Callies or the like, but for the money, an excellent value.

Now if you can put the bolts in yourself and resize them yourself, yeah it'd be worth doing it...but with the ARP 5/16" bolts. Going bigger is/was/always will be a waste on SBF...there's not enough material. The 5/16" bolts look tiny but they're plenty strong unless your pistons are 5 lbs each and you like to use the engine for brakes coming off of a 9000 RPM run. And even then I'd still worry about the block as much as I'd worry with the ARP rod bolts.

GET OUT & VOTE THIS NOVEMBER!!

Last edited by mavman; 07-18-2012 at 08:35 PM.
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post #6 of 11 (permalink) Old 07-19-2012, 02:47 PM Thread Starter
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Re: Rod Bolt modifications - 3/8 for 289

Thank you to all who responded, I was just trying to use USA made parts and to strengthen the bottom end. I thought about the stress issues of tapping the rods, and figured that the new threads were so slightly larger than the current bore, that it'd be a good idea. I also figured there would be more clearance around the big end of the rod and you could polish away a couple of stress risers by removing the shoulder area for the bolt head.

I'd love to build a stroker, but Scat, Eagle and others are asian forgings, I'd prefer to support an American Business with American Products. King offers American Made Components, but they're nearly three times the cost of the off-shore components.OUCH!
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post #7 of 11 (permalink) Old 07-23-2012, 05:55 AM
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Re: Rod Bolt modifications - 3/8 for 289

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Originally Posted by hd_cat View Post
Thank you to all who responded, I was just trying to use USA made parts and to strengthen the bottom end. I thought about the stress issues of tapping the rods, and figured that the new threads were so slightly larger than the current bore, that it'd be a good idea. I also figured there would be more clearance around the big end of the rod and you could polish away a couple of stress risers by removing the shoulder area for the bolt head.

I'd love to build a stroker, but Scat, Eagle and others are asian forgings, I'd prefer to support an American Business with American Products. King offers American Made Components, but they're nearly three times the cost of the off-shore components.OUCH!

Oliver is American. But about $1200 for a set of rods.

Also have a look at Ohio Crankshaft. Everything may be chinese now but at one time they advertised some made in USA stuff.

GET OUT & VOTE THIS NOVEMBER!!
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post #8 of 11 (permalink) Old 07-23-2012, 06:10 PM
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Re: Rod Bolt modifications - 3/8 for 289

Quote:
Originally Posted by hd_cat View Post
Thank you to all who responded, I was just trying to use USA made parts and to strengthen the bottom end. I thought about the stress issues of tapping the rods, and figured that the new threads were so slightly larger than the current bore, that it'd be a good idea. I also figured there would be more clearance around the big end of the rod and you could polish away a couple of stress risers by removing the shoulder area for the bolt head.

I'd love to build a stroker, but Scat, Eagle and others are asian forgings, I'd prefer to support an American Business with American Products. King offers American Made Components, but they're nearly three times the cost of the off-shore components.OUCH!
your OUCH is way parts and most everything is offshore . WALLMART rulers the wallet
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post #9 of 11 (permalink) Old 08-11-2012, 05:47 AM Thread Starter
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Re: Rod Bolt modifications - 3/8 for 289

DanH, I agree, I'd love to see so much manufacturing return to our Shores, I've read that the actual cost difference would be only 10 - 20% versus asia if manufacturing was brought back here. The cost of shipping is so ridiculous, you'd think they ship the parts first class on a cruise ship, rather than a freighter!

We need to build it HERE, NOW, and with Quality good enough to export!
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post #10 of 11 (permalink) Old 08-11-2012, 06:58 AM
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Re: Rod Bolt modifications - 3/8 for 289

hd_cat , someplace around here I got a set of 289 HP rods and SPS bolts still in the package .
intrested in them pm your phone number.

note 289HP rods are factory 3/8 bolts
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post #11 of 11 (permalink) Old 08-11-2012, 08:00 AM
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Re: Rod Bolt modifications - 3/8 for 289

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Another special HiPo part - the connecting rods were machined to take 3/8" bolts instead of 5/16" bolts. The only other small Ford with this rod was the BOSS 302
SOURCE- The 289 High Performance

Manufacturing will not return until government policies are changed.

DISCLAIMER-

The above posted information is in my opinion only. It may contain copy and paste material(s). Your opinion(s) and mileage may vary.

Last edited by KULTULZ; 02-28-2014 at 03:45 PM.
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