The whole premise of getting and flogging a JY engine baffles me. Why go through the extra work? It's not gonna be the solution to your problem.
I was half kidding when I suggested a JY 351. In reality, it's still an expensive solution.
A 351 will withstand your power objectives, it'll fit on the same mount pedestals, and your trans will bolt up to it. Your cam is the only thing that will swap.
The heads will be too small, the intake won't work, the headers won't fit, you'll need a new timing chain, and all of your custom built front drive will have to be adapted. And even after all of that.......it's a stock rod, xxx mile, hyper u crap tic piston-ed gamble.
A JY 302/5.0 is just a bomb waiting for you to light the fuse.....( read 10+ psi)
You will be in the exact same place that you are now.
Fixing what you have is the same thing as above.
Sooner or later, all of the 5.0 guys with forced induction come to terms with with the limitations of the block. Some find out the hard way when they end up with a hole in the pan, water in the oil, or parts sticking out of the block that used to be in the block.
Others just face reality, and take the pill.
The pill is that big nasty tasting one that has the letters D.A.R.T. on it.
The other half of my reasoning for a 351 is that...." On a budget"... Built reasonably, without a lot a fab work....it is your solution. With one caveat....
You just gotta dump that blower.
The 78 mm Chinee turbo on the Monster cost 279.00. You'll be able to find something similar.
You can fab up a hot side using your 5.0 shorties. You're injecting water/meth.....there is no cold side ( figuratively) Whatever intake you find will work. You will not have to rack your brain trying to make your front drive adapt. A set of decent pistons and some good rod bolts. Your willingness to accept lower power gains till you find a better set of heads, and a much lower machine bill than a dart block option will potentially get you back to a place faster than any path involving that jag blower.
I'm the king of beating stock sht to death. I broke a 351 in half exactly the same way a 5.0 fails. ( it took a fuel solenoid failure and a severely rattled engine making 900 hp to do that though)
I split a 460 cylinder apart when I rattled that engine off the line ( Again, probably 700+ hp,...too much timing, too much nitrous, not enough brains, too big of a head, too much, too soon( like a 350 shot, off the line))
" I guess I shoulda kept my mouth shut when I starting bragging about my car...."