Thread: 4.88 gearing question for 1/4 mile

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My buds 64 Nova has 4.88's with a glide, but has only run 1/8th mile with this gear. He runs a 28" tall tire amd leaves around 2700 to 3000. He will be trying the 1/4 mile but wants to know a approx. shift point to hit the traps at the same RPM as the shift point.

Hard to now without knowing what mph he expects to turn in the 1/4. What is his RPM, ET and MPH in the 1/8? Regardless of track length, he should shift just past the power peak of the motor.

Thats the problem. His cam is peaking at 6500. I told him shift at 6400, car will shift around 6700. I think he'll be good with that. You see, he's all signed up for Pinks All Out at Zmax Dragway, which is 1/4mile. Really wont be able to test before raceday, so were tryin to figure it out beforehand. Were not sure how many time runs he'll get there.

He'll proly run out of gear before he gets to the end. Or run out of cam.
Should be close though

Originally Posted by Stu Cool

What is his RPM, ET and MPH in the 1/8?

7.08 @ 96mph. Shift @ 6000, over line @ 6000

From what I have seen they only get two time trials and they need to be consistent. Sure would be great if he could find some place to test before hand, even if he did not get times, just got a chance to run the full distance. If he finds himself running out of gear, he can short shift it and let high gear pull longer. That would probably slow him down, but would at least keep from over revving without lifting.

Pat

Pro Stocks run about a 4:30-4:43 ratio and they are turning alot of R's. I ran 4:30's and was running out of motor.

Originally Posted by bigdude

Pro Stocks run about a 4:30-4:43 ratio and they are turning alot of R's. I ran 4:30's and was running out of motor.

But, I think they're running a rear tire somewhere between 31.5" and 33", which accounts for the lower numeric gear..... Couldn't swear to a tire that large, my experience on big tired door slammers is a bit outdated....


As for running on Pinks.......Hmmmm, wouldn't be a bad deal except your name would forever be associated with the idiot host of the show.....My reputation is already bad enough that I could never stand the notoriety!!!!!

Originally Posted by Stynie

7.08 @ 96mph. Shift @ 6000, over line @ 6000

that is going to be around 11:10 in the 1/4

We run 4:88 in ours. last year with the small 355 motor it launched at 5500, shifted at 6500 hit the traps at about 7000 at 125 mph with a 12.5x 30 tire. car ran 10:70's

John

I would recommend running a bigger tire 30" should work ok with the 4.88 putting you through the traps about 6500 for about 120mph... Or keep the 28" tire and go to 4.56:1 should be about right.... Rule of thumb for shift point is 10% higher than power peak then fine tune higher or lower from there. Good luck with the Pinks deal... I went last year and had my quickest time ever the one run I got on test day before rainout... Day of the show both my test runs were off turns out I broke a valve spring on my one test run (d'oh!)

-Chris

Hey boys cool site, my car used to 1/4 mile car . with 430 gears. 11.90 @114mph. used to shift at 6200-6500 cross traps at 6000 -6200. well its been 2 + years since its been down the 1/4 as im in 1/8mile country. Changed heads, springs, and added more gear. As Stynie said im concerned im gonna be out of rpm at the stripe. Its a stroker with a 1500 -6500 power range. My concern is seeing 7K at the stripe. Its a old piece but consistant bracket racing car. Bobby

Thanks for all the help guys.

Originally Posted by skids72

I would recommend running a bigger tire 30" should work ok with the 4.88 putting you through the traps about 6500 for about 120mph... Or keep the 28" tire and go to 4.56:1 should be about right.... Rule of thumb for shift point is 10% higher than power peak then fine tune higher or lower from there. Good luck with the Pinks deal... I went last year and had my quickest time ever the one run I got on test day before rainout... Day of the show both my test runs were off turns out I broke a valve spring on my one test run (d'oh!)

-Chris

No funding for a gear change right now. I still have my 430's on the shelf but that would make me a little slow for Pinks.

i run a 29 inch tire with 4:88's this year im switching to 5:13 gears and a 28 inch tall tire!!!! i am only crossing the line at 62-6500 in the 488 combo. time to get up there a little more!!! this year shifts at 8-8200

Next weekend is the big day . I will post results....

Originally Posted by Dave Severson

As for running on Pinks.......Hmmmm, wouldn't be a bad deal except your name would forever be associated with the idiot host of the show.....My reputation is already bad enough that I could never stand the notoriety!!!!!

amen