I found a company called South West Engines. They seem to have every used engine on the planet. They offer a 3 year warranty on their engines parts and labor(don't know how they can offer the labor like that) free shipping In the US. I think I saw a 2007 Hummer H3 3.7 engine for just over 2k. They claim to go through them. Remove any sludge internally, steam clean external and ensure all gaskets and seals are gtg with a compression test. Only other option for a 3.5 to 3.7 swap I guess would be find a smashed 3.7 in a Colorado or a canyon. Doubt we can find a smashed 07 H3.........,,,,lol . My H3 I got a few months ago was totaled per the dealership I got it in Paris KY. When I got the title in the mail a few weeks ago guess what? Clean and clear! I have dumped at least 2k in it already. Had it in the body shop all day today aligning the entire front end, hood fenders, adjusting doors and body lines. Guy did a fantastic job! Pulled both fenders and found that the last cheese dick that did the body work was an idiot or just slapping it together to push out the door. They didn't do any rust preventive measures at all on the welded body parts and frame. My guy blasted everything sealed and painted it all correctly. Hood lines are now perfect as are the doors! They even took pictures for me through the process they did. They took the entire front end off the truck! I had missing body bolts all over the place too. This body shop that I have never used before spent over 8 hours on my truck doing all this for me and charged me for 3 hours of labor @ $46 a hour! Total bill today $138.00. I was like are you sure? I must be really living right! Great Body Shop on Ionia Michigan!