I want to add a stereo and speakers to my '68 A-body. Any ideas on the max speaker size and locations. It's a convertible and there appears to be some space in the rear quarter trim and cowl side kick panels. Any ideas for mounting the radio? I want to keep the stock AM radio as is.

you can get aftermarket kick panels with speakers in them. a pair of 3.5s will fit in place of the 4X10. You can also have the factory AM radio modified for FM and to play your iPod.

I bought a set of rear plastic door panels that had holes cut in them for 6x9 speakers and they worked well! I sure wouldn't do that to originals though. The front kick panels with the speakers in them work well, always for sale on eBay.

My son's 67 Dart convertible has good speakers up front (low-mid in the kick panels and tweeters in the dash) and a pair of indoor/outdoor speakers mounted to the front end on the trunk floor. you can't hear those with the top down, but who cares at that point. The head unit is mounted in the glovebox.

I am making similar plans for my 67 Barracuda convertible, but since all of my bezels are cut in one way or another I will probably mount the stereo in the dash. I've got some narrow speakers that I'll probably build a box for each and mount next to each wheelwell. Again, they won't be audible with the top down, but I'll have some front speakers for that.