340 has no balls

cubic inch/HP the X headed 340 is/was the finest SB ever produced my friend. BBblock guys have always feared them. I had a 68 340 in my 70 duster and it was the stongest mopar I've ever had (Ive owned some mild big blocks as well). Worst case it needs to be freshened up /bottom end rebuild spun bearing etc. Best case you have a timing problem, worn cam,floaty valves , vacume leak, wrong intake/carb combo for the heads etc. I would start with the timing.