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Topic: 289/302 rods (non-Boss)
From: Phoenix, Arizona
Registered: Dec 2001
posted 01-10-2002 07:58 AM
Would drilling 289/302 rod bolt holes to take 3/8" hardware (replacing the 5/16" bolts) weaken the rod?
From: Spencer, WV
Registered: Jan 2001
posted 01-10-2002 10:29 AM
Years ago some people would drill out the rods for small journal chevy 11/32" bolts, which are between 5/16" and 3/8" in size... and there was a lot of debate on whether that did more harm than good. If you look at the rod, you'll see there isn't much room beyond the stock size.
Using larger bolts is NOT needed anymore. Back then, bolts were not near the quality they are now. A set of ARP wavelock bolts will handle all the stress the rod itself is capable of generating. I use 5/16" ARP pro series bolts in my 289 rods, and haven't had any problems. They have seen 7k rpm more times than I can count. The standard wavelock bolts are excellent, and half the price of the pro-series. They should be all that is needed for all but the harshest use.
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
From: Lyons, IL, USA
Registered: May 99
posted 01-10-2002 11:42 AM
Mike is correct. We used to install 11/32 chebbie bolts or 5/16 SPS bolts in std 289 rods all the time. It seemed that the rods kept their shape a bit better with the 11/32 bolts, but at the expense of weakening them. They would occasionally crack. We even used to install 13/32 390 HP bolts in 289 HIPO or Boss 302 rods. The "bigger is better" syndrome was the norm in the 70's.
Todays ARP wave loc or B&B HP bolts are so good that the likelyhood of them failing is almost non existant.
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