Re: Radio antenna angle -
 

Since I was questioning the angle of the antenna, I thought I’d also help with a problem that some of the members might have.
The new aftermarket antenna I got from LMC (same as others I would suspect) may all have this problem.
The existing hole from the factory (you can tell if it OEM factory because the hole has a slight notch) is designed for a slightly different antenna base. The one from the kit will need to have the rubber bushing/gasket glued in place to hold it while you tighten down. Also the lower mast brace is too short; I had to make a new one from a piece of flat bar aluminum.

Picture 1 shows the original and the new heavier long brace. I was able to use the supplied speed washers and wrap-around.

Picture 2 shows the hole you have to drill to mount the brace through. It also shows the new brace mounted.

Picture 3 shows the assembly braced at bottom.

Pictures 4 shows the antenna mounted.

Re: Radio antenna angle -
 

Hey Jake, I ran into the hole with the slight notch in my truck. Only not this hole. The dealer punched a hole top center of my dash, and mounted a Buick clock. The whole install had me thinking it was a rare factory option. I think the dealer used a similar punch to get this hole up where a flat mounted generic antenna would ride pretty close to plumb. You did an excellent job of working the unit to the hole you have, but I sincerely believe that hole was not there when it left Pontiac.
The antenna I received looks to be a twin to the one in your pictures. The bases are the same to my eye. I used the template and it dropped in plumb, and bolted easily to the included bracket. Just now I went out and laid tape and measured the installed antenna on my truck. These pictures show the measurements I recorded. 7 1/2 " from front leading edge of cowl to center of hole, 6 1/4" from body crease line to center of hole. The hole on your truck appears to be way off from these measurements. Knowing LMC, they may have given you a template from a 1964-66 GMC antenna. If I could , I would opt for a flat based antenna and be done with it. But the only way this 90 dollar kit is ever going to fit as designed, is to tap a 5/8" hole at these coordinates, and plug the notched hole. No grinding/painting, and it will ride where it was originally supposed to. It will look as if it has always been on the truck. You would have a hole to fill and paint. You might hunt another cowl piece that has no hole and save filling the hole. Might be easier to get a good result. Good luck whatever you decide to do,GM

Re: Radio antenna angle -
 

Thanks, I really HATE getting the body man to weld up the hole and repaint. I think I'm forced to recut/sand the bottom of the base to try to correct the shape angle. Last night while fooling with it, I stepped on the end of the cable and broke it - maybe a sign from the BOSS that I should start over ;). I can replace the cable no biggie, I'm going to try and sand down the base, then it THAT won't work fall back to the weld and repaint.

The really crazy part is that it will be for looks mainly as I plan on having the radio gutted to fm/iPod. I HATE BEING ANNAL RETENTIVE.

Re: Radio antenna angle -
 

Let me know how your radio project goes. I saw a drop in FM unit they are making now. No cutting. I found a 1963 Chevy truck radio, and just changed the front glass to my 1960 GMC one. It was the only year a solid state AM factory radio was made that would drop in a 1960-61 hole. GMC had the same radio in 1963, but the glass was different. I may ad an FM converter one day. I rarely play the radio. I love the sound of the tailpipes. Never get bored of that sound. GM

Re: Radio antenna angle -
 

I have a stock AM and am having it gutted to be FM/iPOD, it has the GMC logo on the dial glass.

Re: Radio antenna angle -
 

Looks good!

I shaved my antenna off, welded the hole with a slug, and put a bit of bondo over it before prime & paint. By the time it was done, and quality paint was put on (as well a some other repairs)
The radio was gone anyway...so I figured I'd make it like it was never there to begin with. (photos in my journal thread, if you care to check it)

Also, there was no notch in the antenna hole for my '66, for the record. Just a generally-circular hole as if drilled, not punched.