You dont have to run a regulator. I have a large Weber down draught on my Ford ute and an electric fuel pump that pushes about 7psi. It runs a little rich ofcourse but I have no drama with too much pressure, actually has a nice pop pop sound when you back off the go pedal or change gears.

If you cant afford a regulator then you can make a nice simple one that is effective and will cost you very little.

Simon