Any progress on these?  Is that a grade 5 or 8 Allenbolt?

Well, Fastenal is not correct, maybe they just don't sell them. It is true that hi-grade flat head bolts are harder to find than for the socket head versions, which is why I recommended in an earlier post that you counterbore the holes rather than counter-sink them. Mil-spec 130,000 psi tensile strength bolts exist, for instance see part # 93401A610 at McMaster-Carr. They are kinda pricey, but this is not an application where you want to get cheap. The other reason I recommended you counterbore rather than countersink is that the countersink places rigorous geometry accuracy between the plates, i.e. if the hole pattern in the countersunk plate is a bit off compared to the threaded part, you are adding bending loads to the bolts as you tighten the cone-shaped surfaces together. With a counterbore, making the through-hole slightly bigger accommodates minor hole-pattern mis-alignment without adding bending loads to the bolts. You could try giving Fastenal the McMaster-Carr part number and see if they have something comparable. Note that the part number I gave is for a certain length, but if you google McMaster-Carr and the part number you can pick the length you need and get a different part number.

relim
 
Nothing wrong with the bolt you selected. I might have looked for a way to use a low-head socket bolt instead of the counter-sink, but it's your car, and as long as the hole pattern matchup is good, you'll be fine. Please post more pictures when you are done.

If looking for brake parts might look here. http://www.piratejack.net/
I have not used them but it looks like they have a lot of stuff we could use.
If they don’t have a switch you can make work then hit a junk yard and get one off any car along with the plug & bracket if it has one or you will need to make one. Bolt the bracket to the peddle bracket and wire it into the old wires. IIRC AMC had a kit to do this from what I hear.
Dave ----