340 magnum from 73 dodge dart rebuild

I don't think you and your uncle are on the same page. A 73' 340 puts out about 240 net hp. So with a nice tight rebuild, a slight hyd cam upgrade, maybe a rpm intake with a good exhaust system will get you around 270/275 real hp. In a light early Abody that has the ability to be a 13sec smooth daily driver.

Then you have to think about that 7.25 rear that's probably in it. Regardless, i think, engine wise, 4k should get you a top notch build on the long block even if it requires boring.

Good luck and enjoy the journey. Just do as much research as you can and remember the old saying.....measure twice/cut once. :)