First time at the strip!

I finally got the chance to take my Duster to one of the Test and Tune nights at Bandimere Speedway near me... What a blast! With the engine in my sig I ran a best (out of 2 runs) of 15.3 sec. @ 93 mph. This is with a stock 7 1/4" open rear with 2.76 gears (and BFG street tires), 904 trans (with 2500 stall converter), AFB 625 carb, factory-style dual-snorkel air cleaner, and Hedman Tight Tube headers into dual 2.5" X-pipe exhaust.

Obviously the rear end is the biggest limiting factor, I didn't even get out of 2nd gear by the time I hit the traps!! 60' times were pretty bad, 2.34 seconds...! I have an early B-body 8 3/4" rear waiting to go in, how much quicker would my car be with 3.55's and sure-grip (and street tires vs. slicks)?

Also I think my engine could use a bigger carb (I'm thinking Holley 670 Street Avenger) and open air cleaner, how much would that give me? Lastly I have a 284*/.484" MP purple cam lying around, if I swapped that in how much quicker would the car be vs. the small Voodoo cam that's in it now?

Just bench racin' here guys any and all comments welcome...