Just went through a similar exercise with my Unique 289 FIA and my 1987 302 motor, a roller cam HO motor that is basically stock. The 87 motor has forged pistons, slightly dished. You need to talk to people who build race cars & motors, get their opinions, and then filter opinions to get to where YOU want to be on HP and driveability. Pure race, drag strip, or primarily a street cruiser, with some serious reserve HP??
A couple of names. The best 'carb guy' I've come across is a guy in Washington State, Don Gould. Builds race cars, loves small blocks, and personally runs a 318 Mopar that puts out over 400 HP for drag racing. Don sells Demon carbs, but more than selling them, he personally takes them apart, insuring everything is 'right', and will baseline the carb based on your motor, cam, car weight, rear end, etc. Comes pre-tuned. He will also talk you or your mechanic through the process of recurving your distributor and setting the correct timing. Don's web site is
www.4secondsflat.com and his phone is 503 627-0728. He has helped a lot of cobra owners by helping with carb adjustment, etc.
Don recommended a "cam guy" to me, Jim Dowell, of Racer Brown in Maryland. Don will go through similar exercises as Don, and he will custom grind a cam for you at the same price as the stock off the shelf cams from the big name companies, but he will be able to offer more custom service and a bigger bang for your buck. Really knows his stuff. Little things in addition to the duration and lift, but also addressing lobe separation and making sure you have a cam that just doesn't produce power at high RPM's, unless that's what you want.
Heads. A new set of Aluminum, quality heads, changing springs to have the right ones for your roller cam, are going to be in the $1400 neighborhood by the time you are finished. The best two choices based on my research, in terms of flow numbers and HP produced not just at high RPM's but "under the curve", from .10 - .50 lift, are the AFR 165's and the Trick Flow Twisted Wedge heads.
AFR's are cast in the USA, and are extremely popular. Heads are around $1250 - $1275, plus new springs for the roller, takes you up to $1400. I was going with AFR's until Unique told me I would have to modify my exhaust header / manifold in order to use them. They recommended Trick Flow or Edelbrock. Several other head distributors / engine builders recommended Trick Flow, or AFR, and all the flow numbers pointed to these as the top two, basically with the same CFM numbers.
Since I thought I'd have a problem with the AFR's I went with Trick Flow Twisted Wedge heads from Panhandle Performance, their Stage I package. They buy the casting, polish the bowl, use higher quality valves than the stock ones (Ferrea Racing Valves) and do a competition valve job, plus use the upgrade springs for the roller cam. Just got them, and they are beautiful.
The big issue is balance, from everyone I've spoken to.
-302 block 1987
-forged pistons
-new cam, 221 duration @ .050; .500 / .500 lift; 10 deg lobe
separation
-TF Twisted Wedge Heads flow 254 / 193 (intake / exh)
at .500 lift
-Edelbrock RPM Performer intake manifold
-Comp Cams pro magnum roller rockers
-Speed Demon 575 carb
-Projected HP 350 at 5800 RPM
Careful with the intake manifolds. Volume of CFM must be balanced with Velocity. More velocity is important so that the vaporized fuel / air mixture moves quickly into the cylinder. Don told me to stay away from the Air Gap intake manifold on the little 302 motor, too much volume and not enough flow. Does not work well at lower RPM's. Has to get up to 3000 RPM to run better.
But again, these are opinions, but at least opinions of people who have built race cars and motors for 35 years or more.
You should be able to get to around 400 HP and still have a car that can be driven on the street. Have fun with your research, I have had a ball with mine, and know a lot more about motors today than I did 3 months ago!!
Rick