A buddy of mine had a stock AM in his '66 Coronet 500 with an FM convertor stashed in the glovebox. Worked for him.

For my pickup ('54), I've got a bunch of pretty good stuff (that's several years out-of-date, but was high end at the time).

Eclipse 5303 head unit for the glovebox (which works okay since the glovebox is in the middle of the dash, and the head unit comes w/ a remote).

I also have an old 10" MTX sub that I may try to make an under-seat enclosure for, or just upgrade to a newer style subwoofer with a lower 'q' factor that works in a small box, depending on whether I can get a big enough box stuffed under there.

I'll re-use my Aura component drivers. Best sound I could find (at the time) in the under-$1K speaker market - and I listened to the Diamond, Quart, etc. offerings.

Unfortunately, (due to theft) I don't have my 3 way 24 dB crosssover; I'll have to get another crossover - I'm a big fan of separate amps for tweeters and mids.

Advice: spend as much as you can afford on the mid and tweeter speaker drivers - they're where the magic is. If you go for coaxials, ones that have an aim-able tweeter are preferable. If they aren't set up to be bi-amped, cut the leads off the tweeters, and put some separate leads on 'em so you can run them from a separate amp. Subs aren't such a critical item - they've received SO much R&D over the last fifteen years that even relatively cheap ones are pretty good. A single 10" or 12" is usually sufficient for musical reproduction (and even moderately high-power BOOM) in a typical '60's sedan). Since I got out of the scene a few years ago, there's been a lot of work spent on getting a lot of sound out of a small speaker enclosure (one that won't eat your trunk).

Most passive crossover sets (ones between amp and speaker) are CHEAP, and most tweeters are crossed over at too low a frequency; this leads to 'spitty' vocals (especially female voices) at higher volumes) - active (between the source and the amps) crossovers and separate amps solve a lot of this.

Subwoofers are really important to musical reproduction. A lot of kids go overboard on them, and neglect the rest of the equation (BOOM, BOOM, BOOM, while the licence plate frame and trunk lid buzz...). One of the best - and many of the worst - sub setups I've heard were 'bandpass' subs. Off-the-shelf stuff is basically hit-or-miss here; usually the latter. Bandpass boxes should be custom tailored to the sub and car. A musclecar-era car is a great candidate for one, however, since there are often speaker cutouts in the parcel deck under the rear window where the sound can come thru. For myself, I'd build an enclosure onto the bottom of the package deck to mound a sub in a BP box to feed thru there. It'd save some trunk space; you'd hardly see it with the trunk open - but just a single driver tucked up towards the front of the trunk will suffice, as long as you have speaker grills in the package deck to allow the sound in.

Buy amps bigger than you need (i.e. 60-100 watts per channel for speakers that you'll run at 30-50 watts); turn the gain down a little, and you'll have tons of headroom. Also, you don't need high-end amps for casual listening. The little tiny bit of sonic nuance you'll pick up by going to a high end amplifier will be lost as soon as you fire the car's engine (ask how I know).

Buy a head unit based on features you like; they all have CD drives and tuner packs that are way better than you'll need - any $100 name brand unit is going to be fine. Go shopping at the stereo store and pick which one you'll like to use.

Also, unless you're running a really big bass amp, I wouldn't run out and put stiffening caps on its input. Any decent quality speaker wire and power wire should suffice - there is VERY little to be gained there other than making sure the conductors are sized appropriately to the power load.

Probably a little "TMI" for your question; if so, here's what I'd leave you with: Allocate half the budget to your speakers; choose a radio based on the features you like.

Good references: Car Stereo Review Magazine, crutchfield.com

-bill