have you fitted a chip in the ecu to bypass the boost cut out ? I believe its about 10 psi on erst's.

Are all your plugs, leads, dizzy cap, rotor etc all ok ?

I had a similair problem to yours which I cured by soldering a 1 inch piece of wire between the two terminals on the rotor arm, keeps a constant and strong spark then all the way up the rev range. Hope this helps

Duncan