For my money Heidts has not only the best design but also the highest quality and best instructions. That said, asking which Mustang II kit is best is like asking which carb is best Edelbrock or Holley. You'll get a couple dozen different opinions.
Here's a Heidts setup on my '53 PU. Was installed in one afternoon.
Centerline, thanks for response, did you use manual or power on your build? After I posted question I realized there would be many different opinions. Lots of discussion on this site about the topic. Just dont want to spend the $ W/O reasearching.
On the '53 I used a power rack. I also put a Heidts unit on my pro-street 41 Chevy, but on that one I used a manual rack. The only real difference between the two is that with the manual rack you need to use two hands when parking. With the power rack you'll need some sort of device to lower the pressure if you use a GM pump. There are spring units that modify the pressure of the pump itself which Borgenson sells and there are also adjustable pressure reducing valves which Heidts sells. The advantage of the adjustable valve is that you can easily dial in the "feel" you want. On my '53 I used the spring type unit on my GM pump simply because at the time I didn't know about the adjustable unit.