[8D]
It would have been like a day without sunshine otherwise!
G.G.S., this is the type of return style regulator I was reefering to: Fuel Pressure Regulator

 

Everything you're telling me makes sense in my head. But I talked to a local mechanic who really does nothing but build street performance motors and he said the regulator will lower the pressure but the volume of fuel pumped into the carburetor will still be too high. High enough that it will result in a blown motor. Thoughts?

 

Not everything your mechanic is saying is making complete sense to me.
Let's start with his last comment about a blown motor. The issue with running a carb with a high output electric pump is that the needle and seat can't hold back such a high amount of pressure. What will happen is the carb will flood over and fuel will start pouring inside and out of it like a fountain since the needle and seat won't be able to hold the fuel back. So if he means the engine will catch fire and blow up, yes it could. If he means excess fuel will make the engine blow apart, I really do think the engine would flood out and kill before anything gets damaged.
The pressure on an electric pump for the TBI isn't terribly high compared to a more conventional FI setup. And honestly, if the carb is new, it would probably handle it on it's own for a short while. But the pressure is still a bit too high to run without a regulator.
About the pressure/volume comment. The needle and seat in the carb can only hold back so much PSI. Stepping down the PSI with a regulator, to put it into tolerances that the carb can handle will prevent fuel from pushing past the seat as described above, and avoiding an overflow. The volume of fuel flow by the pump is an issue when the float drops and the seat opens. But since the pressure regulator has lowered the the PSI of the incoming fuel, the needle and seat can close again.
Also, that's the beauty of using a return style regulator. Any fuel that doesn't get through the regulator, just returns to the tank. That creates a nice, even, constant flow of fuel, without the pump constantly trying to blow through it.
Maybe your mechanic can explain how the fuel coming in at 4 PSI that can't blow past the seat, will make the engine blow? I'm curious.
Using a regulator with a higher output pump is nothing new, it's done all the time. As far as first-hand experience, a few years back, my brother put a 350 in his Fiero. It was a V8 Archie kit, and V8 Archie used to be literally two minutes from us. The car was built there, and as you may or may not know, the stock Fiero, like many FI cars uses a very high pressure pump (much higher than yours). An adjustable regulator was used in-line before the carb, just as we're talking about here. No problems, no leaks, no running issues, and especially NO blown up motor.

 

See, that makes sense to me. And I guess because he's built many motors, I was trusting his "knowledge" a little bit too much. I think I may throw this mechanic to the scrap pile and stick with this. This is twice in the same week he's made an off-the-wall statement and THAT'S not something I need to be dealing with while building.

About blowing the motor, he did mean that the motor would actually catch fire. I just think the words he chose weren't the best words available. But what you're telling me about the return line set-up logically and mathematically makes sense to me.

I'll definitely be back...I'm sure I'll have another problem to share with the community. I really appreciate the help. If you'd like me to clarify anything, I can do my best. There isn't a whole lot I know about these things, but I'm rapidly making progress.