CJ, yes 12 ' seems big for your 130 mph car. One thing to keep-in-mind is you can "tune" a chute by adjusting where all the lines come together. BY chocking the lines you make the chute act smaller, because it's catching less air. Also keep-in-mind Garlits stopped driving because of eye problems from de-acceleration from chutes. Use common sense here.
I adjusted my 1'st chute on my 60's nitro JrFueler, so it would stop soon enough but not throwing me into my belts. At some tracks I raced in the MidWest, I opened it up more because of short shut downs.
Have fun !
Jon Hansen, Heritage JrFuel racer, and Hayden Wheels.