I just recently started a engine swap on our Jeep with 180,000 miles. It has taken 3 years planning between, 5.3 LS $17,000 installed), Cummins Repower ($12,000 installed) and a company in Phoenix 505 Performance (supposed to be $8,600 installed) that builds a 4.1 Storker motor from your 3.8. Our Jeep is my wife's daily driver so timing was critical and the main reason we went with 505 as they build it, crate it and send it to you for a weekend swap. Send them your block back and drive on. WELL that didn't happen quite as planned. Although the Jeep is running now and has a nice improvement in power it took 3 weeks, 48 quarts of oil, 3 oil pan gaskets, 3 timing cover gaskets, 3 water pump gaskets, Camshaft sensor, crankshaft sensor, knock sensor, new plugs and new wire set to get it to a running stage. Here is the pre swap dyno numbers. 149 HP and 173 Tq. Not bad for a 180,000 miles Jeep with 4.88 gears, 3.5" lift and 37" tires and hydro assist steering .