Doug has the 4.0 heads for 350 or 375, and you can get springs for a cam installed for a few bucks more if you want to run a cam Rick.
If I was going to replace mine now I would get my shortblock rebuilt local, and try the heads from Doug, and add the cam, assemble my own kit- 2500 or so for a budget build up.
I looked around for a complete engine when I replaced mine- 150k clogged pick-up. I wanted to add the comp cam, and ended up getting a local machine shop redo and assemble the short block, and rework the heads(guides,springs) and I put it all together. I paid the machine shop something like 1300 for the short block and the head work. The cam, lifters, pushrods, rockers were another 800 or so, and 200 for gaskets& misc. so 2400 or so for my 30 over 4.0 with the comp cams 410 cam, new pistons, bearings, timing chain, oil pump, pick up- guides on the heads, springs, cam, lifters, rocker arms and shafts, and correct length pushrods. Its a nice combo for my daily driver.
If you want a bit more power with a cam change, and can do a little assembly it may work to get the new heads, and get your(or a core) shortblock rebuilt with a cam for your own engine kit. Time is the question.