I currently have 29.5x11.5x15 Hoosier Quick time pro's on my 70' chevelle I have always ran 11.5 to 13 psi and it has always hooked hard 1.39 to 1.45 60ft times. I have just stepped up my engine program and have started spinning off the line my 60ft times have droped to 1.49-1.58sec. you get so few passes arround here on test & tune days its hard to work out some of these problems.I was just wondering if any one has tried running 17-20psi in these tires? I think with all of the extra touque I am hitting the tire too hard I may need extra tire press. my buddy said when the car launches now it is almost completely crushing the sidewall.any thoughts?

I have run 20 psi for the last 4 years. 28x13.5x15. Did some extensive testing with more than 20 passes on the same day testing pressure from 15 or 16 to 22 psi. 20 psi consistently gave me the quickest 60 fts.

thanks I will try going higher on the pressure the most I have ever tried is 15psi . I am knocking on my 1st 9 sec. time but just cant get thru the tire spinn now . I went a best of 10.15@133 on Friday at super chevy w/ a 1.48 60ft. time. If i could get back down to 1.40 It would put me there.

Good Luck, that's really moving...Let me know how you do..

Tom

I had to run 19 psi in my slicks to get them to halfway hook,,,I'm not sure why its so hard to convince someone to put more air in the tires,especially with our nose heavy,heavyweight chevelles :confused:

In my son's Chevelle when we had the 482" motor even when it went 1.40 sixty foot numbers it still got stuck at 10.0s. The day we finally broke thru it went two 10.00 times and then he pulled it up on the converter which killed off some of the "flash" and it responded with a 9.98 @ 133.7 MPH. It may be necessary to get new tires to make it happen also. P.S.... A built up Turbo 350 will get you a tenth and 1 MPH over the Turbo 400 and are quite reliable if you do proper burnouts.

Thanks guys, I am going to try and get to the track this week end and see if more pressure will help. Also may add some more ft. end travel I have had it limited to 4" upward.

Originally posted by Rons70SS:
Thanks guys, I am going to try and get to the track this week end and see if more pressure will help. Also may add some more ft. end travel I have had it limited to 4" upward. Did you try the Shock Nut Trick ?

No what is the shock nut trick? I have travel limiters installed on the upper controll arms.with out them I have 6.5" upward travel from the resting position.