Square headed bolt for CSB - alternatives?

[Freight]

I, like probably many of you, have ran into the bolts that hold the CSB in place, just spinning. Looks like the previous owner had a field day with mine, as the track on the drivers side is bent and unhappy. I was able to hammer it back into place but am struggling mightily with getting them to not spin when tightening. 

Is there an acceptable alternative to these $10 bolts, like a carriage bolt perhaps? 

[Blue Shadow]

They need assistance in making any movement a very tight squeeze. 

I have wedged a screwdriver in the channel to prevent bolt rotation. 

[Mike W.]

I can see how it could be a problem, especially back east where lots of salt is used. But I'm not sure a carriage bolt is a good idea, I might be overstating it, but I think they're made out of the weakest steel for nuts and bolts, I would guess the factory part is much stronger. Just a guess, but it might be significant. Might not, but might.

[Freight]

They need assistance in making any movement a very tight squeeze. 

I have wedged a screwdriver in the channel to prevent bolt rotation. 

I ended up managing to tighten them by way of a very mcguyvered series of channel locks and a box wrench. My extensive screwdriver collection seemingly didn’t have one that would truly cooperate. 

If these ever have to come out again, I’ll have to replace them and given the condition of the slots, I think I’ll need some with tighter fitment. Seems like the type of thing that wouldn’t be terribly difficult to beef up using new hardware and a mill. Future endeavors

[Freight]

I can see how it could be a problem, especially back east where lots of salt is used. But I'm not sure a carriage bolt is a good idea, I might be overstating it, but I think they're made out of the weakest steel for nuts and bolts, I would guess the factory part is much stronger. Just a guess, but it might be significant. Might not, but might.

You’re probably right. Carriage bolts are the first thing that came to mind that has a shoulder like the oem part, though I’m sure there are others. 

salt is so much fun. The land where no frame rot means “rust free”

[jimoreno]

I just made some from M8 square head bolts in SS that I got from Amazon. Ground off the head to make them slimmer to fit in the channel and used a small metal cut off wheel to make the shoulders on the sides of the stud. I made a bracket out of 3/16" angle to support the original muffler bracket that bolts to the transmission since the long tube Stahl headers connectors ended up exactly at the factory location for the bracket. I didn't realize that there is an difference in height from one side to the other (I guess I should have looked at the transmission mount) and just ordered a longer set of bolts to use one with a spacer.

[szacsi72]

Personally, I bought some stainless A2 bolts and TIG welded them to a thicker, bigger, longer 304 plate.

While there, I recommend you to upgrade the CSB to an E34 one. It's plug and play and beefier