Instead of using an F150 pump, why not use the GM TBI one? and with tons of pickups and suburbans in wrecking yards that had the TBI 350 in them, you could even grab the fuel lines off one..just shorten them to suit and go from there ?

(You'd get the right fittings to screw right into the throttle body that way, plus the return line, the inline fuel filter, flex sections, etc)