speakers

For an am 8track the 74 tsm says the speakers are 3.2 ohm. Will 4 ohm work? I have always heard that using the wrong impedence speakers could damage the deck. Any opinions or thoughts?

I have a 1974 Javelin with Motorola Multiplex AM Radio w/8-Track.

The speakers in my 1974 Javelin were the original ones that came from the factory.

How could you tell the ohms of those speakers? What did the rear speakers look like?

The rated impedance of a speaker is a nominal rating as the actual, working impedance ( resistance ) of a speaker varies considerably in actual operation. Virtually all impednace ratings are either a averaged rating or a minimum rating. The slight discrepancy between a 3.2 ohm rated speaker and a 4 ohm rated speaker speaker is insignificant.
Furthermore, going to a higher rated impedance speaker such as an 8 ohm speaker where a 4 ohm speaker had been specified will NOT cause any harm to the radio or an amplifier. Going to a LOWER rated impedance speaker could ( but not always )cause an issue as the potential current draw of the lower impedance speaker could cause overheating of the radio's amplifier section under higher volume conditions as the lower rated impedance speaker will draw more current at higher volume settings. On the other hand, newer speakers ( as compared to the truly cheap, OEM grade speakers originally used ) are typically of much better design with vastly improved cone materials, more powerful ( not neccessarily heavier ) magnets and better voice coils which make the modern speakers more efficient. This means you get more output from the speakers from a given amount of input power from the radio's ampliifer. The net result is that the amplifier is likely to have it easier with a modern speaker that it did with the OEM junk irrespective of the new speakers rated impedance.

Using a 8 ohm speaker where a 3.2 ohm or a 4 ohm speaker was used originally will mean that the radio's ampliifer will deliver less maximum power into the 8 ohm speaker. But... if that 8 ohm speaker is only slightly more efficient that the original 3.2 or 4 ohm speaker then the actual net effect on the radios maximum output level ( without distortion )may be an increase in usable output and certainly fidelity.

My experience with the Motorola built AMC radios of the late sixties and early 70's is that they are are of low usable output power, in the order of 5 to 8 watts or so, for the mono radios and roughly the same power for each channel on the stereo radios. The amplifier sections of these radios is passable from a fidelity standpoint, but nothing approaching the high fidelity amplifiers that we how have in virtually all aftermarket and OEM car audio systems of today.

If you want the OEM look then the best you can do, short of hiding another sound system in the car, is to use the stock radio with modern speakers that will fit into the original AMC factory openings and locations. Noisy and intermittent volume and tone controls on these older factory radios typically will respond to modest application of a volume control cleaner spray to the inside of the control. This requires that the radio be removed from the car and the cover opened so that the nozzle tube of the cleaner spray can be inserted into an opening in the "can" portion of the control so that spray can reach the resistance element and wiping contacts inside the control. Just a little spritz and some quick rotations of the control shafts are all that's usually needed to get the controls operating consistently again. If you're not familiar with such things then just remove the radio and take it to any tv or electronic repair shop. They'll know what to do.