A pretty standard set-up is 50 wt. oil with a #1 piston. I usually run 40 wt. with a #2 piston. Center spring depends on your track. If your track is smooth and has a lot of bite, you should start off with a Silva black center spring (8 lb/in), if you track is really bumpy I would start with a Assc. silver (3.85 lb/in).
I run the #2 Piston with 70 weight oil......With a green Assoc. Buggy Spring
(front)...on my local flat track and car is planted real good...If your flat track
is a little bumpy I would try the Assoc. silver spring.....