ID my rod bolts

[TheNovaMan]

I really should have taken pics, but it's such a hassle when your hands are oily and you have to go inside and get the digital camera...
Anyhow, my motor is an LS6 454 crate motor that was rebuilt a few thousand miles before I bought it. I figured it had the GM-spec knurled rod bolts, but that was before I figured out the short block had been apart - the crank says "R30 M10" on the front counterweight in yellow paint marker. I don't have a stretch gauge or a mic, so I didn't dare pull a rod cap... the rod bolts have an hourglass indentation in the top. Any ideas on what they are?

[TheNovaMan]

Anybody? Are these the miserable OE knurled bolts?

[white00gt]

I'm only guessing at this but they sound close to the same as the TTY bolts GM sent me with a steering colum I did the other day. The bolts had hours glass shapes just below the bolt head that are designed to snap off when the bolts are "there".. hope this helps.

[Brad87gt]

I am sure the R30 M10 means the rods were turned down .030 under and the mains were turned .010 under.

[TheNovaMan]

Brad, that's what I figured too, and that's the only evidence I have that the short block has been apart. Well, come to think of it, the decks look like they were cleaned up with a cutting head that wasn't perfectly orthogonal to its axis of rotation... but anyway, the hourglass was an indentation in the head of the bolt, not below the head of the bolt. I'm just hoping whatever chucklehead rebuilt the short block resized ALL the rods (not just the spun one) and put new, non-knurled bolts in them. I guess the only way to know for sure is to take one of the rod bolts out, but that's just not happening. The motor is in the car. Maybe this winter.....