Rochester Monojet Question

[Tkrysl]

Hey All,

I was cruising down the road today when I hit the gas and the truck went haywire. I had to limp home after having to keep my foot on the gas to keep her running. It acted like a vacuum leak.

Upon inspection, it looks like the screw that attaches the carb to the throttle body backed out and she's gone.

Does anyone know the size of it? I figured it would be a quick trip to the hardware store if I knew the size. I've been searching to no avail online for any indicator of my question.

Thanks,

72 GMC C15 250 inline