My Special has had an extremely irritating squeak that occurs at any time the car is moving and constantly at highway speed...a high pitched shreeking...imagine a knife edge against a piece of metal...just realized what it is - the throttle linkage bolted to the firewall. It's a vertical shaft held by two brackets, top end connects to the rod going to the carb, bottom end connects with rod to gas pedal. There needs to be plastic or rubber bushings between the shaft and brackets, so you'd have to drill out the brackets to a bigger size, or if you don't care about originality, just update the whole overly complicated and sloppy mess to a cable system from something newer and eliminate the hole through the firewall that lets noise/fumes in (if your rubber boot is as rotten as mine was, anyway).
If you have your engine out, NOW WOULD BE THE TIME to do this as it's not fun getting this thing off.The upper bracket is cherry pie, just a 1/2" socket for one bolt...the lower bracket must be unbolted from underneath, you can just barely get a 1/4" drive ratchet and 7/16" and a 5/16" sockets on the two bolts. If you have one of those 'micro' 1/4" ratchets, that would be the trick. Once I got it off, I scored the shaft at the upper spline before taking it apart, otherwise I think that lever could go on any which way, and the whole deal would be misaligned.
Trust me on this guys, make it a priority if you are anywhere near running your car, or you will regret it! I tried uploading a pic but it is too wide...the 1200 pixels wide limit thing is pathetically small, I took that pic with my damn cell!