have you heard of the volvo head swap. makes it a dohc. the na 2.3 put out around 100 bhp. the turbo put out around 200 to 220 bhp depending on the year but all ways more power then the 5.0 from the same year. if you put the volvo head on a stock na motor you make about 200 hp. there is a few people who did that instead of going turbo on the mustang sites i go to. on a stock turbo block with stock boost most people make about 280 to 300. you install the volvo head you need to weld a block of metal on the back side of the head. run one external oil line and mod the timing belt tensioner.
you could try to find the after market big bore head that they stop making. or if you want to spend a crap load on just a head that bolts on you have elsslinger(sp?)
if you need help getting a rebuilt turbo 2.3 head i can help you get one from under 200 plus shipping. my step dads work sells so much product there cost is so cheap, and he only has to pay cost for parts.(the sell to fleets and auto shops like napa)
the 2.3 block is pretty dam strong and theres alot of guys making close to 700 hp with it.
if you need any advice hit me up.
pics of the car can bee seen here. takes a bit to load. the kid i own the car with is the red head hes kinda picture happy lol.
http://gallery.mac.com/whytei#gallery
before
after we rebuilt it and painted ect ect. you have no idea how hard it was to sand the paint off where we left it metal since masking with high temp paint sucks.
any one looking to carb a 20b rotary shack sells a dizzy for that.