It must really stink to have to wait that long for a tune. Jeez! Just so you know, you are already at or above 300rwhp with the
Vortech installed. A bone stock 302 will make 300rwhp with a blower. I have a friend with a '93 and is just getting started. His car is completely BONE stock under the hood and has my old V1 sc-trim from my previous SSC installed. His made 306 to the tires on stock pulleys making 6 pounds. He's happy with that. "For now"
Once you get yours tuned, it'll be there.
As for your question: I guess I can be considered one of the old timers since I've been playing with these since the early '80s. Back in the day there were no dyno's and tuners to be found around here. There was practically no aftermarket parts for these cars either. These cars were cutting edge at the time.
Guys added parts and guessed at the power their cars made. One of my friends was the first guy in my area (that I know of) to install a Vortech, it was an A-trim. Until then, I had never seen a centrifical supercharger before. LOL, His car idled high, surged, blew head gaskets, ect, ect. Noone knew how much power it made but it as fast(when it was running.)
300 horsepower was a goal for sure, but that was just overall horsepower. Noone thought about rwhp. There was no internet so we all read HOTROD magazine articles, followed the articles and added parts accordingly.
We bought
K&N filters, removed the air silencer, bumped the timing, added underdrive pulleys, added a powerchip (module), welded
Flowmaster mufflers into the stock exhaust and later bought gears if you could afford them. LOL
If you did all that your car made 300hp. LOL WRONG!
But hey our cars felt fast, sounded good, won alot of races and we had alot of fun! Lost alot too! Thankfully somehow I survived all that and I'm still here.
These days 400-500rwhp is a healthy goal IMO.
A 500rwhp foxbody with good tires will just about outrun anything basically stock on the street. "Including the new 5.0 Mustangs"
Not gonna say how I know that
Sorry for my long winded post but I tend to ramble.