Normal 289/302 rods use 5/16" rod bolts. People have honed rod bolt holes oversize to 11/32" and used Chevy rod bolts.
289HP and Boss 302 use 3/8" rod bolts. 289HP rod bolt heads were rectangular while the Boss rod has oval/football shape heads.
Reaming the 289/302 rods for the 11/32" small journal Chevy rod bolts is outdated nowadays. With the advent of MUCH better rod bolts/materials, it became a thing of the past 25 years ago. The area of the rod where the bolt passes is extremely thin, and reaming it out further weakens the rod more than what you get with the larger bolt. Plus, with ARP bolts, it's completely not needed.
I was running 289 rods with 5/16" ARP bolts in the old 289 headed 306 when it was running 10.63 @ 129 on a 200hp nitrous plate. The ARP bolts, especially the Wavelock Pro series, are extremely strong. Never had a rod related issue, and ran them for years... and countless nitrous bottles.
Yes, the Chevy bolts were a popular modification back in the day, but I wouldn't do it now. More of a chance of going backwards than forwards.
Good Luck!
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