OK, a last idea - you may have a spun balancer hub. If it has spun, you'll never set the ignition lead correctly.

Remove the driver side cam sprocket cover and rotate the engine to align the marks at the sprocket. Is the crankshaft mark on "0"? If not, the balancer hub has spun.... it's not terribly uncommon for it to happen.

If you find the balancer marks don't agree with the cam sprocket marks, the only way to be 100% certain where the problem lies is to remove the front cover and recheck the marks on the crankshaft sprocket and oil pump case to see if they agree with the cam sprocket marks. If not, the cam timing is off..... if they agree, the balancer has spun.

Frank