I hadn’t given much thought to a crossover issue as I have a single plane intake (Holley SD) and headers. I honestly thought a single plane did not have a crossover.
I have considered that I’ve had a fuel issue however. The truck lost 2-3 tenths last year - doesn’t nose over but it lost numbers everywhere. I sort of chalked it up to needing to freshen the engine up. I probably need to rig up a temporary fuel gauge taped to the window to get a read on what my cruise and WOT pressure is. Lower pressure = lower fuel boiling point.
I do have a timing limiter plate on the distributor from 4secondsflat for more initial timing (20deg if my memory is correct) while limiting total timing. That certainly improved drivability.
You need to know what the fuel pressure is not assume. If vapor lock was an issue which it could but I doubt nearly everyone would be plagued by it. I had a 360 mechanical pump which drove me nuts. In the end with a gauge it acted up. Fuel problem lost pressure. New lift pump cured it. I took the pump apart as it worked and had pressure then it would act up. Ended being a piece of soft like lead or solder in a check valve. I then ran a filter on the pumps inlet.
