I wouldn't buy a reman engine from my experience with just buying two sets of reman cylinder heads. I found so many things wrong with every cylinder head that I sent them back and brought my original heads to a good machine shop and had them rebuilt.
Some of the issues I had with reman heads were: Gouging/scratches on the head sealing surfaces, one head had the wrong camshaft in it, 3 out of 4 heads had leaking valves, mangles camshaft bearing surfaces, debris left in the oil passages and there was probably more wrong with them that I hadn't noticed. My point is, if reman heads potentially come with that many issues. Imagine how many issues an entire engine might have that has been built by somebody that either doesn't know what they're doing or doesn't care.
If I were in need of a new engine. I'd either buy a used, running, low mileage engine and then either rebuild my engine in the meantime if I choose or consider having a reputable shop rebuild it for me.