After a lot of time and money, my car 60-fts slower this year than last. Here is the basic info on the car:
- Street/strip 70 Duster, has run 10.50's @ 128 mph, 1.55 60-fts.
- 440/500 with ported Eddy heads and 260 degrees @ 0.050 solid roller. I shift at 5.8K rpm. Engine is very torquey
- 727, 9.5” converter, flashes to 4500 rpm. I'm foot-braking the car
- Steel body, 3300 lbs With me in it
- Calvert mono leafs and shocks, Caltrac bars, 9x30 M/T ET Pro Drag radials
What's changed lately:
- SS springs to current Mono-leafs
- New Calvert rear shocks, set to 7 (used to be Comp Engineering)
- Re-positioned leaf-spring perches (they broke). Pinion angle now 2-degrees down to driveshaft. It used to be a bit more than this
- Bias-ply 10.5 x 30 changed to current 9x30 radials
I was out at the ANRA event over the weekend and got 60-fts anywhere from 1.9 to 1.58. The tires spun a lot. Even the 1.58 was spinning pretty good. The 1.58 came from 11 lbs In the tires. If I run more or less pressure it results in more spinning.
My pressures on the radials are below M/T's recommendations, but the low pressure is needed to prevent spinning. The tires also move an inch or two on the rims on each pass (even after gluing). Speculation is that the low pressures contribute to this
The 9-inch radials were recommended to me. My gut told me to go with 10.5” tires, but I was told the 9-inch tires should work fine
My 10.5” bias tires seemed less finicky and more consistent
