Hi, Looking to install a thumbwheel radio with 8 track player into my 70 challenger dash. My Mopar Muscle hardware book is calling for 2 1/4-20 x 1/2" hex head bolts with loose washers which have 6 small teeth under the washer. I located them but they appear to be to large and coarse to go into the tapped holes in the bottom of the radio. The holes appear to be a fine thread and seem to be maybe 10-32?? My book shows the bolts I have but it shows them next to the regular R11 radio with the two knowbs? Could the thumbwheel radio have used a different bolt? Anybody else have dealt with this mystery?

As far as I know, All E bodies 70-74 will use the same bolts .
It doesn't matter if it's a Phillips , a Motorola, or a Bendix ,
AM , AM 8 8track , AM FM, knobs or thumbwheel, all E body radios use the same
bolts . They are unique to E body , due to the size, not found on A B or C .
I do not have any extras laying around at the moment.

Greg