I cabbot get my 78' 280z running right. It will start adn idle, but it wont rev or allow any load to be placed on the motor.

Most of the fuel system is replaced or new and it has a new aire flow meter.

I need serious advice or im gonna junk it.

Off the top of my head, it sounds as though your timing advance is not working. On the earlier 240's this was a common problem, the advance mechanism INSIDE the distributor was supported on a thin plastic piece with some ball bearings in it. After time the plastic would dry out and break, and freeze (or almost freeze) the advance mechanism so that it would cause the motor to act as you've mentioned.

Hope that helps.

Enrique

My first thought was timing also.