just rebuilt runs bad

Sounds to me like you need to CONFIRM that the timing mark is actually correct. This is easy to do.

Make or buy a 'piston stop' like this:

http://www.jerrybramlett.net/images/pic_installation.jpg

Remove no1 plug, make sure it's "down a ways," then remove the battery ground. You may have to play with the length of the stop.

Wrench the engine around until the piston stops. You don't want it "at the top" but at some random distance down a little. At this point, make a temporary mark on the balancer right under TDC on the timing tab.

Do the same thing after rotating the engine CCW against the stop. You will now have TWO temporary marks, and true TDC will be halfway in between. If the original mark is correct, that is where it will be