I ran the largest softest Good Year Tires that is offered for a 15" diameter wheel. Think they were 17x34 IIRC. Anyways On a marginal track, the car picked up from a 1.14-1.16 short times, to consistent 1.07-1.08 short times. This was going from 7-7.5LBS to 5-5.5 lbs. FWIW
MPH actually didnt change much (even though I picked up .15 seconds overall), I guess due to spinning and wheel speed. About 143-144mph in the 8th

[color:"red"]65 Hemi Belvedere coming soon [/color]
[color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]