Have you looked into wider and/or taller slicks?
There could be quite a bit left on the table just in a tire change.
The 24.5x8.5x15 should fit, taller will give a bit more footprint as well as the extra inch in width.
Gearing calculator use could show it better or worse than the 23" they also make in 8.5" wide.
The 26x10x15 might be a tough fit besides finding wheels for them it staying in 4x108 but there are some 15x9 and 15x10 in 4x100, not sure how wide a wheel is appropriate on a drag car though.
I have done quite a bit of gear selection, RPM best to shift at, etc work on cars for the track and for when I raced bicycles even, one of the things I used to a great advantage and sometimes a short shift is faster than a redline shift depending on where it drops you into the torque curve(at least for road racing and autocrossing where I have done my best)
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There should be more than enough gain in the tune to get you into the 11's of course so that is a great place to work on but you might need the new tires when you add the 5th injector as well to limit the wheel spin more in 1st.
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I am sure your car is quite a hot topic amongst some of the big engine cars