I have an 85 camaro that i've installed a 95 Lt-1 into.fuel pressure is my problem.
I understand that engine requires at least 42-50 pounds of fuel pressure can someone suggest a pump to use for this application,I currently have only 38 pounds of pressure.

 

How are u checking the pressure? U should be checking it with car idling and FPR vacuum plugged.

 

Have u considered an adjustable FPR?

 

If you have 38 PSI with the vacuum line attached, then you are in the ball park. with 20" of vacuum on the FPR diapragm, that would give you about 48PSI without the vacuum line attached. When vacuum goes up(meaning more suction or more "inches" of mercury in suction), fuel pressure goes down. The point is to maintain 42-50 PSI pressure differential across the injectors. 20" of vacuum is about -10PSI. You need Pressure and Volume. If you lack the fuel volume, then when the demand rises, the pressure will drop. So you are looking for a pump the will flow the correct pressure at all GPM rates. One N/A horsepower requires roughly .45 - .50 lbs of fuel per hour, so 300 horsepower will need about 150 lb/hr or about 25 GPH.

 

i installed an inline fuel regulator with a fuel pressure gauge,it reads 38 pounds,if i open the throttle up the pressure drops.
engine runs good at mid rpm ranges but stumbles on acceleration and loses power at higher rpms..

 

If the pressure drops your filter is plugged or the pump is failing...

 

What is the pressure without the vacuum line attached to the regulator? Pressure should be 42-50 PSI. Check the pressure without the line attached, pressure should not change regardless of the throttle position when the line is not attached. I agree with TTOP350, sounds like a plugged filter, plugged strainer or a failing pump.