I'm running a turbo with fuel injection on my 71. Once down to a 1/4 of a tank or more we have serious fuel starvation on acceleration. Is there a difference in fuel pickup lines from the tank in higher psi systems vs the lower psi system?
Unfortunately it is a fact of life with the gas tank that you will have these problems. I had a 72 turbocharged and it did the same thing. I was boosting 19psi on my motor. Nothing like hitting 19psi and then the fuel is cut, sending your head into the steering wheel. The problems is there are no baffles in the early tank and the pickup is not exactly a good design for fuel injection. You can remove the tank, cut it open and add baffles. You can also undo the bolt on the bottom of the tank and run your pickup from that. I solved the problem by taking out the old tank and installing a fuel cell with race foam and a sump. Good luck.
Use the tank from a 75 280. It's a little better than a stock 240 tank, especially for fuel injection. the best thing to do is add baffles and a new pickup for a serious car if you don't want to go the fuel cell route. here's a cutaway view of the stock 240 tank to show why it's so bad.
greg 71 240z