318 cam

Bone stock 79 318. Hughes whiplash 340 cam. Stock heads stock bottom end. Stock convertor Stock valve springs. Stock 727, 3.91 gears cam and intake. Screams even without water for 20 minutes and coulda went longer but pulled off the win in that time..
Did you install the cam @ 102 ICL? and if so have you checked the cranking compression?

I would be curious to know what the cylinder pressure is like.