I am trying to figure out whats wimpin' out first, distributor or fuel pump without spending any money on expensive diagnostics.
I am the 2nd owner of a 70 el camino, 300 hp, 350. it's a factory 4bbl. the only modifications are a high voltage coil and an electronic ignition upgrade from pertronics.
I just adjusted the valves and that seemed to help some, it needed it anyway. and I dropped the timing down from 11 degrees advanced to 8. I know the factory says 4 degrees advanced but this engine loves the higher setting. it's a burn out any time anywhere kind of car. I tried many different settings in 2 degree increments and settled on the 8-11 awhile back.
it is a factory fuel pump so I wouldnt be supprised if that was it, but how can I be sure?? I don't have disposable income to buy and try things, I kinda have to know. and it's only at the high rpm's around 4000. thank's in advance, mike

If it's fuel delivery, like pump or lines or filter or whatever, it will usually pull hard through first and then fall on its face halfway through second or something like that. If it's the dist it will fall down at the same RPM no matter what the immediate past history is.

could be a lot of things but definately fuel or spark related for sure. does it start breaking up at 4000 or just fall on it's face easy? usually if you get a gurgling sound it will be fuel related.

it does screamin' burnouts, and hauls tail anytime, anywhere but just looses intensity and kinda starts sputtering like its starving. that's why I suspected the stock fuel pump. but I have also heard it could be the distributor. I have fairly new plugs and ok plug wires, and the upgrades mentioned in the original post. let me just say too that this car was, and is well taken care of, and is always kept well tuned. I don't get many chances to open it all the way up in my commute it's just something I have noticed and it bugs me.
it pulls hard though, almost 80 before it shifts into 2nd, just kinda gives up around 4 grand. thank's for the insight guys!!