What should fuel pressure be at WOT with Holley 650 Double Pumper on a 355?

I'm getting 3-3.5 when I initial gun it in 1st gear, and it dips down to 2 at top end of 2nd gear(wasn't able to check 3rd and 4th).

You probably need 4-5 psi minimum at the end of the track.

Got to do a little longer run- at the top of first i get 3.5-3, top of 2nd gear I get 2 psi, and top of 3rd gear I get UNDER 1 PSI.
I changed the cam and thought I would feel a little more 'kick' then I actually did and I think this could be my problem.

Any cheap internally regulated mechanical pumps out there that will support my combo?
Its a 355 with World S/R Heads and a xs268 solid cam(230/236@.050) and 3/8th line. I don't want to go with the Carter 172 and have to deal with all the fittings.

A Carter 120 gph would probably work fine.

My ride runs no different with 3 or 6 psi at the top end....But 4 to 5 minimum makes me feel a lot more comfortable.

I have 3 Carter 172's for SB if you change your mind.

Doesn't matter what the absolute number is; it mostly just needs not to drop between idle and the end of the track.

Most carbs will work entirely fine with 3 psi. The main thing, is that when you set the fuel bowl level idling, it stays at that level always. You can't calibrate a carb around a fuel bolw level that changes. It's impossible to set one up right if the FP drops at high RPMs and loads. It will lean out and do terrible things like put holes in pistons.

As long as it stays the same, or goes up, throughout the course of a run, it's OK; even if it's only 1.5 psi, like a boat.

If it drops during a run, it's probably not the pump itself. I sure wouldn't try to fix that by just sticking a bigger pump on it. Try a lightweight drive rod first, such as from Moroso or Crower. It could also be a restriction in the line, which would usually be a buildup of th ecrusties in the pickup line inside the tank, or a plugged filter sock.