OK I have the dash speaker harness, still not locating anything for the rears?
View attachment 25601there were definitely 2 back there.......................
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The crossover and OE wiring are not likely to work with a modern aftermarket radio, at least not well. The OE stuff used common grounds, often chassis ground, of which aftermarket stuff made after about 1985 isn't particularly fond. I won't get into the particulars, but it would probably have significant noise. For the corner dash speakers I'd still recommend the ones I linked above, wired directly to the new radio. If experience has taught me anything, those 3-1/2" speakers are shot; I'd guess the paper cones would rip if you sneezed on them.
The rear speakers you have pictured above are definitely not OE Chrysler; in fact they're 1986-'95 GM speakers used in G- and H-body cars of that era (RWD Monte Carlo, Buick Regal, Grand Prix and FWD Delta 88/98 Regency, Buick LeSabre, Pontiac Bonneville). They're actually not terrible speakers when used with their original enclosures. They also might top-mount (sit atop the package tray, beneath its cover panel) and mount easily with speed nuts clipped to the metal tray. The downside to them is finding the long-discontinued connectors for 'em.
I think this is the under the seat harness???
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I tried to ID this harness going by the connector closest to center and was not able to find anything like it in either the '73 or '74 service manual. I can find that type of connector, just not with yellow and white wires. I'm also tired and probably not as focused as I could be.
I think I got these from charger man, front mounting is different not sure I can adapt,
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The bane of putting a decent center speaker in an E-body is that oddball football-shaped speaker. I do not know of a direct-fit replacement offhand. One of my dash pads shows evidence of someone attempting to use one with the standard 4"x10" flange shown on the Pioneer, but only two of the four holes were drilled and I've no idea whether it actually fit. Those parts were long gone when I got the pad. You're on your own here, as I've not yet determined what I'm going to do in that hole.
The same stupid speaker was used in 1971-'74 B-bodies. On my '72 SE, I used a rear roof speaker from an early '90s Suburban that had a forward-facing tweeter (which faced the rear in my car). The trick there was that the B-body grille is a metal panel with screw holes around the perimeter of the speaker, so it held the speaker in place. I don't think I'd want to risk my plastic grille to attempt it on my Challenger.
rear is pyramid & there were 2 covers in the box?
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Do you only have one Pyramid speaker? Those would work well, assuming you had a pair. Pyramid ain't top-shelf stuff but it's not lousy either. They would have to be bottom-mounted (below the metal package tray) though--they won't sit down flat in the existing speaker cutouts. I don't know of any aftermarket speakers that will. I'm going to cut my Challenger so I can top-mount mine... bottom-mounting kind sucks.
Don't worry about "how much power they'll take"--even the most expensive speakers will still work on a 2W signal.
The speaker grilles for the Pyramids? I'd toss 'em. Hide the speakers under a stock-looking package tray and be done with it. It looks much nicer that way.