I'm gunna thro my 2 cents in. Spib you said the motor was hard cranking? Make sure your timing light is working right or set right. The motor at 38 to 40 degrees should not strain to start up. I know for a fact to much timing will kill the motor above 5000 rpm. It happen to us when we used a timing light with the dial on the side. It was on 38 degrees and we set the timing at 38 degrees. The car ran but missed at 5 to 5500 rpm. I always use my old timing light with no dial on it.