Can I replace 4.7 With a 4.0 They are both 1999 jeep Grand Cherokee

Thanks for the Advice, Problem is I do not have the original block that came out.

You're most welcome. Grand Cherokees with 4.7L engines can be found at local Pick-a-part / Pull-a-part type wrecking yards, and an entire engine can be had for UNDER $300 with warranty, probably slightly more at a regular salvage yard. Also, you can check craigslist etc I have seen them for sale there too by someone who totaled their Jeep and only had liability so they were parting it out.

They totaled it because the 4.7 was junk and not worth repairing AGAIN !!!

4.7's are not under $300 on the east coast anyway. The cheapest i found was $900. I had to throw a oil pan, seals and exhaust manifold on passenger side because it was out of a Dakota so it dumped in a different spot.

It can be done but you'll need to swap the PCM, transmission, I believe you'd have to swap transfer cases as well, motor mounts, and quite possibly the radiator I cannot remember which way the in/out ports are on the radiators between those 2 engines in the 1999-2004 WJ grand cherokees. The engines were both options in those years so you'd need all the 4.0L hardware to swap them.

I have both 2000 jeep with blown 4.7 . And i have the 2002 with the 4.0 engine low miles 70.000 so i should have no problem making the swap. And yes the radiators are diffrent. And I'll need to change the key to match the PCM also . Thank you