Decided not to drop the trans just yet. Instead continued to fabricate the exhaust so at least I can run it without my ears bleeding. Now with the exhausts on its obvious the vibration is there at even 800 rpm and just gets worse as it rev's up. checked and double checked the timing , firing order and plug gap. some other I got, engine number VIN is 9A171805 date stamp above this is 12-21-78 so assume that is 21st dec 1978 ?
Also noticed transmission mount is ripped is complete ripped in half, so that could contribute to it!