engine troubles

I placed an LT1 into a 97 Jeep Wrangler. The engine is a 96' crate with 92-93 fuel rail and intake. Well the problems i am seeing is gas in my oil. Very low oil pressure due to this. The driverside O2 sensor runs real lean when warmer and on the gas. I did notice the fuel pressure would drop some (30 - 35) when on the pedal. I believe i may need to add a larger fuel pump to solve the fuel pressure issue. Gas in the oil ??? Oh, the vacum test looked fine @ 20. Any ideas....:( :(