Before you take a big step backwards, consider some progressive alternatives.

1) Different fuel pump. Unless you are going to concours events and some judge will crawl under there to ensure you have the proper fuel pump attached, just replace as necessary with a more modern, cheaper, generic FI fuel pump. There's nothing magical about the D-Jet pump that I know of, it's just like all the other FI pumps.

2) If your motor is stock, just get D-Jet working properly. It's relly simple, 3 sensors (MAP, IAT, CLT), some trigger contacts in the dist, and a crude accelerator pump throttle switch. If it isn't working right, it's probably just one of those few things or the wiring between. Most people seem to diverge into tinkering with D-Jet to try to get it to work right instead of finding and fixing the actual fault.

3) If you modify the motor a bunch, then keep most of the FI hardware and put on a modern computer system to control it, like Megasquirt. For less than you'd spend on an underwhelming Weber downdraft kit, you could get completely configurable moder fuel injection. In this day and age, it's simply a far superior solution.
--
'63 PV544 rat rod, '93 Classic 245 + turbo