Fuel Pressure ?

What's the stock output of a 90 (Non-NO) fuel pump pressure wise? I'm in the middle of swapping in a 5.0 that needs at least 40psi.

Generally, it is adviseable to keep the stock pump, replace the in-tank pump with another unit, or add an in-line pump to the stocker when swapping in FI V8's?

Thanks,
Jay

I've been running my stroker at 45 lbs for a year and a half (18000 miles) with no problems - stock is 39 lbs on the early 4.0s

Both the 87-95 4.0L Jeep and the 5.0L Mustang run at ~39 psi (3-bar), and the stock pumps are nearly the same for fuel delivery. Both are regulated to this 3-bar pressure (and can be modified to raise the fuel rail pressure).

Either pump is good for ~350hp.

The most common problem with either injection is heat soak with an external pump, the in-tank pumps run cooler.

Some of the built 302/347/351 Fords run a Porsche external fuel pump for the added volume and adjustible pressure (again, only needed if the power output is high).

Considering the EB's with late model Exploder heads and MPI run well, an XJ should run very well (without the extra weight the EB carries).

Thanks for the info. I have another question:
How many fuel lines come/go to the tank on a pre-HO? I thought I had 2 supply lines and 1 return, but now I'm not sure and the jeep is not here...

Jay

One supply and one return (up to 96 when the OBD II system changed to a returnless 49 psi system).