The best way to figure the top speed is calculating it out using the rpms, your tire diameter, and gear ratio (please don't try to do the math while making the top-speed run !!), not the highly inaccurate factory speedo, even if you do have a 94 - 95 with the higher reading unit.
My best so far was last year, 4650 rpm in 5th with 3.27 ratio, works out to about 146 mph. Now that I have a raised top, better exhaust, and a pulley this year, it's time for another go. I want 150 mph !
Just have to get my rear fender lips trimmed a bit, my new slightly taller 18" tires occasionally rub just a touch on big dips in the road, especially at higher speed.
Oh ya, here's the formula :
rpm x loaded tire diameter / 336 x final drive ratio (rear gear ratio x 0.7 OD for auto trans, or x 0.75 for stick)
cheers
Ed Nicholson
SCCoO