Even if your not changing to a different rate secondary spring change it out for a new one every year.
So brand new springs all around
EPI maroon and 10-60's as said above
66-44.46 helix, stock secondary spring with 2 delrin washers
21/39 gearing
stock RR needles clip 2
fuel screws 1.5 turns out
1.0 air jets
i run 410 mains with a tempaflow (410 would be what it runs at -20F)
and im still rich but the guy who rides the sled wants it to be super safe pull the rope and go sled.
1.25 ripsaw with 144 studs
Dyno port pipe and silencer
This thing will stand right up and hit the bumper on the ground if you have the right traction.