I have a 1988 yj with 4 inch suspension, 3 inch body and 35 in tsl swampers. I recently put a 350 vortec l31 engine and transmission out of a 1999 yukon in it. I used aa saddle engine mount. I got a conversion adapter from jtr to match up my hybrid np231C/np231J with ss slipyoke eliminator transfer case to the 4L60 4x4 tranny. I custom built the transmission mounts located on the transfer case to the jeep skid plate so I could use the s10 tranny mts. It turned out really solid and fits perfect like the stock yj. A guy out of arkansas made a stand alone wiring harness out of my original l31 harness for $320 bucks. All I need to do now is find a cheap 23.5in rear drive shaft with u-joints on each end with the slip shaft setup in the middle of the shaft. I am very aware that I am gonna have to do a rear axle conversion at minimum to handle the tires and added power.
The problem I'm having is with fuel delivery. I got a 20 gallon tank/fuel pump out of a 1993 2.5 yj donor I bought. I really need to know if the 2.5 liter pump is going to produce the 66psi I need to run the L31 vortec engine? I'm not sure, but I heard a rumor that the L31 has a fuel regulator on the fuel rail on top of the engine. Also...will the stock fuel pump in the 1993 2.5 produce the psi I need? If not, is there another pump I can replace it with in the tank. My friend told me Walboro makes a pump that should fit, but I don't know the part number! I don't want an out of tank fuel pump. PLEASE HELP! I'm ready to get this beast rolling!