Have you replaced your ignition points? My 74 did exactly what you described. My points were out of adjustment and burnt. Very simple fix. Hope you get it figured out.Update. the ajusted the timing, it was quite a bit out, it idles and revs nicely now and the coil isnt getting so hot.
however i tried to take it down the road and as soon as its under any load it bogs down and sputters not driveable.
but atleast it idles