If you have the 4.3 L
CSI system you will need
60-66 psi as MT said or it will not start .
if you have the
SFI system you need
56 psi.
With you having the 4.3l and have the
CSI system make sure you do a leak down test as these motors are known for bad fuel regulators
If i remember rightly if your 8th Vin # is a
W then it has the
CSI system.
Remember when testing you fuel pressure be Careful not to exceed 75 psi when testing with the return hose blocked ( on thr CSI system)
That will kill you fuel regulator(if its not already leaking)
One more thing, when you tested the pressure you had 50 with and without return hose blocked check your fuel filter
Indy
Edit -Just noticed wasted my time on this one its bloody years old