New K-frame bolts?

I got mine off of e-bay

Is there anything special about the k member bolts? Couldn't a grade 8 of the appropriate size be used just as well?

There's a shoulder on the bolt that's sized to the hole in the K-frame...

When I dropped my K-frame the other day, I found that one of the bolts had been replaced with a bumper bolt or similar large thread bolt, but it didn't have the shoulder. If three aren't good enough to locate the K, I guess I should buy one.

Anybody know the size/threads of these k bolts?

5/8-11 x 2" with special shoulder as mentioned above. See description including photo here:

www.amkproducts.com > pdf catalog > page 109-127 > scroll to bottom of page 114.

Probably any vendor of this item has bought it from AMK and is re-selling.

Thank you.

I am puzzled by the original need for a shoulder bolt, it doesn't seem to me that a shoulder bolt allows for any extra manufacturing tolerances, and regarding shear strength in a massive wreck because a grade 8 5/8" threaded bolt versus a 3/4" shoulder, not sure its enough to matter unless hitting the wall at daytona is a concern. Looked at my RMS Alter K and I believe it has 3 large holes and one smaller hole FWIW in the K. The bolts are only attached to 14g? Sheet metal anyway. The only case i can visualize if the factory suspected k frame to chassis movement over the course of say 100K miles, and felt the shoulder style would survive longer.

It's not shear strength.

It's location as the bolt is tightened up. My Taurus subframe has two pilot holes into which one sticks a particular diameter rod before the subframe bolts are tightened. Then they are removed after the bolts are torqued to spec. These shoulder bolts do the same thing except without the hassle of inserting the rods. After they are torqued down, friction keeps the subframe in the right place.

R.