Well thats new to me, i didn't know it would run without a fuel pump.
I don't think it will get you very far.. As soon as you rev it up, it will suck a vacuum on the fuel rails and then hammer the snot out of your injector pistons.. But it will idle as a proof of workability when you are messing with things like I was today. if your fuel bowl was in place, it might idle a little longer than it would without it, because there is more volume, and gravity may help move some fuel from the bowl to the heads to replenish the fuel being used to run. ?? who knows..
Suffice to say, it surprised the heck out of me when I was working on one once, and I turned it over to prime the HPOP and the thing started. I removed the fuel relay, and when I hit it, it started. I shut it down immediately, since I thought if it ran, it must mean the fuel pump was running. And since i had no fuel bowl on it, it must be filling the valley with fuel. And then I realized that it wouldn't matter if the pump is running or not, since there is no fuel bowl to get the fuel to the heads. It must be gravity.
After that, I played with it a few seconds, just to see what it was doing, and see if the HPOP was leaking (the reason I had the fuel bowl off in the first place). It smoked white, and wouldn't rev worth a damn.