fuel pressure regulator or fuel pump, or something else?

[white91gt]

Background:

I have a 1991 GT with 25000 miles on it. I have owned it since it was new.

It has only been on the road for about 3.5 years. It has been stored on and off for the past 25 years.

11 years ago I installed GT40y303 heads, 1.72 rockers, and a GT40 tubular intake with 30lb injectors, with a ProM75 mas calibrated for the injectors.

It also has a Vortech A-trim supercharger.

I also installed a BBK FPR and a Walbro 307 pump.

It started and idled fine, but I never had it on the road.

Problem:

So, I did all of this prior to having a family with kids. I now have the time to get the car out and use it.

I finally got it out last week, on the road, and once it hits 2000rpm, it bogs down.

I disconnected the Vortech in order to troubleshoot the problem and eliminate one of the variables.

I put a fuel pressure gauge on it, and it shows that the fuel pressure drops off to less than 10psi after 2000rpm.

I have already refreshed the gasoline and replaced the fuel filter, I am now thinking that it may be the fuel pump or the fuel pressure regulator.

The fuel pump is really noisy. You can hear it above the engine, exhaust, and blower whine at idle, and in the car when moving.

The fuel pressure at idle is set at 41lbs with the vacuum off, and 35lbs with it on.

Key on engine off, the pump primes up to 41lbs and holds pressure.

I also let it idle without the vacuum on, and when I revved the motor above 2000rpm, the fuel pressure dropped down to 10lbs.

Regulator or pump ? or something else..?

Any help is greatly appreciated.

If you need any more information in order to properly diagnose, let me know.

Thanks,
Matt.