I recently replaced the mikuni with a rebuilt weber, checked for vacuum leaks, installed an electric fuel pump, checked the timing marks on the engine and distributor according to this site's info, and have 2 vacuum lines on my engine (1. brake booster 2.vacuum advance)
when accelerating everythign is fine unless i go over half throttle; after that it stalls and acts like its going to die, unless i let off, then i can start accelerating. Also i can run the engine upto roughly 3500-4000rpms this way(no tach), but it seems like there is no top end.
I pinched off the vacuum advance while the truck was idling and the idle dropped; this tells me its getting advanced right from the bottom of the rpm range. No amount of moving the distributor around will seem to fix this.
Do I need a new distributor?(vacuum diaphram? maybe something different that requires more vacuum to actuate it?)
This truck never had any amount of power in stock form, but after i replaced the fuel pump(electric: made my own circuit complete with fuse), carburetor(weber), de-smogged, fuel pressure regulator, dropped the gas tank, replaced fuel and vacuum lines, checked every wire on the harness, and BANGED MY HEAD OFF THE WALL!
I have no idea what else to do, short of replacing the vacuum diaphram or modding it in some way???
it also seems to be running rich, but i think that is just part of the timing issue