Should be practically a ProStocker!
Here is what spit back out of the Gonkulator - I gave it fairly slippery traction since you mentioned wheelspin even with the 3.08s:.
Torq 205 at 2000 (less than a bone stock 250!)
Torq 268 at 3800 (now it wakes up)
Powr 246 at 5300
Below 3000 it WILL feel soggy, less punch than a stock 250 up to maybe 2500rpm or so. Above that it wakes up.
Shifting at 5400rpm
2.39 60ft
10.15 at 69.7 1/8 mile
15.82 at 85.2 1/4 mile
7.86 0-60mph
Even shifting at 4000, your 0-60mph times should be in the 9's if its running right, at full throttle. REALLY need a tach in there though for any full throttle runs so you can see whats going on.
I always short-shift a new combo on purpose, ie let it shift at 4000 or so - then I see how it clocks out vs the Gonkulator. If its running right, then I let the revs go up. If not, why scream the revs until you figure out the problem?
Your hot combo does like a bigger carb, A 550cfm Holley added 1 ftlb and 7hp for 253hp. However, it made very little diff on the clock:
Same as above, but with 550 Holley
2.38
10.13 at 69.9
15.79 at 85.4
7.82 0-60mph
Point being, if that carb keeps giving you trouble, why not try another one? I usually try at least 3 different carbs on a combo, just to see which one it "likes" best. Even a different 390 Holley, or a 450 Holley, 550 Holley, 500 AFB, 500 Autolite 4100 (I like those on the Chevy 6's) etc. That carb may just be an ornery one!
ON THE DYNO STUFF:
The GOnkulator says 143 RWHP, but I don't find it too useful to compare chassis dyno RWHP numbers, they tend to be all over the place. Good for tuning the car, but the numbers don't mean much.
Best is, get it running right, then hit the strip, get some timeslips. Best "dyno" I know of. And a lot more fun.
