Where's the best place to order a replacement engine with a guarantee?

I have a 95, 4.0, automatic, cherokee, 4WD.

I would consider putting a Ford engine in if it fit. any recommendations?

 

Boy, I cant remember where it was but Im sure I could find it again, but when using google to look for rebuild kits and heads, I stumbled upon a site that had factory engines that were $1500 to $1900. My 99 4.0 was $1849 if I remember correctly. It was basically everything except accessories.

 

Jasperengines.com