Seeing as heâ€™s 18 and on a budget and wants something reliableâ€¦I would MAKE him save up for a decent Top-end kit and perhaps do a re-build of the stock shortblock.
Heâ€™s still a kidâ€¦and at 18 he has no need for a setup capable of 500+rwhp. On top of that, a h/c/I setup is going to be FAR more reliable than any budget turbo setup you plan on doing. Once the h/c/I setup is done and paid for, have him start saving up for a quality turbo kit. Not only will it give him time to get acquainted with 300rwhp in a lightweight foxbodyâ€¦.but it will teach him the power of saving.
His 84 Ranger is pretty light, not sure on the weight, but I would think it must be in the 2,500 lb range and with a welded up rear end, the 302ci he has in there will light up 1st and 2nd (using a C-4) pretty well.
It is looking like he can get a quality turbo, hardware, B&G hot side and then fab the cold side for a little more than the cost of quality H/C/I, injectors and headers that would make 350-400 HP/TQ and he'll save the cost of changing the gears in back like he would for the N/A motor.
From what I've been reading, the main problem with the cheap systems is the hot side and it sounds like B&G makes a good hot side setup.
Wouldn't a 350-400 HP/TQ turbo engine be more dependable than an N/A engine making the same power? I'm pretty sure the mpg would be better when he's not on the gas than if he went for the N/A.
In order to make some decent N/A power, he would most likely need to jump the compression up to 10.5 to 1 and that wouldn't be the best for when he switches to a turbo.
Re-ringing the engine and swapping bearings is pretty cheap and it will give him some good experience to port his stock cast iron heads himself. If he learns how to port cast iron well, aluminum will come pretty easy for him in the future and doing the intake fabrication will jump his skills up a little more as well.
It is looking like he can rebuild the engine, buy the turbo, parts and still have less than $4,000 (maybe less than $3,500) into the car, which wouldn't be bad for a 350-400 HP/TQ Mustang that should still get over 20 mpg on pump gas.
While he is only 18, he has been driving since his age was measured in single digits. He taught my wife how to drive my Deuce and Half when he was 9 years old and while 350-400 HP/TQ is a lot, it is the next step from his lighter truck that makes 100-150 less.