Your MPH shows potential for the 12.0 range. I would suggest you "slip" the clutch in 1st, rather than "dump" it. It's a lot like driving on the street with street tires. We managed to get the 60' under 1.9 with true street tires (not D.O.T. "slicks") with moire power than you have (400 Pontiac, mildly built, 410 RWHP, 480 lb. ft.). The Muncie has good gearing, too, but with the 5-speed, you should have a slight edge there (gearing, I mean).
I would hold the revs right at 3,000, and let the clutch out SLOWLY. As the tires started to bite, I would let it all the way out and hammer the throttle AFTER the car was well underway. Sometimes, the tires would break, but usually, it would hook and go.
Drag racing with street tires can always be an adventure. Be sure you understand the difference between "street tires" and "street legal tires".
In any case, you've done just fine. Your car has more in it, and you'll find it with some experience. That little Ford is a very good place to start. Once you've mastered driving the manual in drag racing, you can move "up" to a faster car with confidence. You can even save some money and make the little Ford MUCH faster.
Don't be led astray by those that will tell you you CAN'T win bracket races with a manual. You most certainly can. It DOES take practice and skill. I have one customer with a '65 GTO convertible that goes 12.0/11.90s (depending on the "air"). It has TriPower and a 4-speed, and he's won three bracket meets in the last two years and been to the final round on several more occasions.
Jim