Stock GM truck sterio much better

[Fast68Chevy]

I replaced the aftermarket Boman CB/Radio unit in the 78 with a stock GM sterio/cassette player yesterday, even though the cab is literally crumbling.

With the same speakers, (Blapunkt 6"x9" 100 watt RMS 300 watt Max) it sounds tons better and clearer than that CB unit did. (Also have a 40 watt x 2 amp from Wally world).

The CB unit had its own dual antennae set up, so I scrapped all that and drilled a 7/8" hole in the middle of the hood and installed a new antenna.

Were the stock GM radios pretty decent in their day, or was the Bowman just weak? How many watts do these GM sterios push out? This one looks identical to the one in my stepdads 82 K-10....