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Your Builds / Photo Gallery / Re: Intro...Geez I really miss drag racing
« on: January 19, 2017, 08:35:36 PM »
Hi Chuck
Hey gonna send you a PM here in a second...
Hey gonna send you a PM here in a second...
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And after all that work you are still dealing with a 60yr old block. If you are lucky to have a machine shop at your personal disposal, fine, if not and have to pay for all that plus normal block prep, you are about $2 shy of what a premium used Donovan goes for
My experience on 12" wide rims, with the 31x12x15 D2585, and the 33x12x15, D1288 is it looks like , by looking at photos going thru the lights, is 2585's grow at least 2 , and the 1288, less, because they weigh 31 lbs, and grow less.
But I assume you are asking about tire growth trying to figure rear gears, expected MPH, & rpm. With looking at the RPM's , gears, & MPH, I have found that the 2585's grow a bit more, because they are lighter [ 26 lbs] and with narrower rims they also will grow more. But the bottom line when I look at my RacePak, and ET slips, it looks like if you just plug in the tire dia, ie 31" [ 2585] or 33" [1288] that the RPM is very close to the MPH when using one of the on-line formulars. My 2585's at 190 mph matches the ET slip by using tire dia of 31 1/2". Which of course doesn't make sense compared to the photos, but what we have going on is the converter slippage. So just figure 1/2" more, like 31 1/2" or 33 1/2" to figure on gears, RPM, & speed. i helped out another JF car when he was having traction problems, at the hit, with his 2585's on 11" rims, I let him use my 2585's on 12" rims, it helped, he ran a 7.04. But he did not like the 12" rims because with his 387 ci SBC, he ran lower MPH, because he couldn't pull the wider rim but he would smok'm more often. Part of the difference in our two cars combinations, is his was superlight 1355 lbs with driver [ that's why he built the smaller motor at 3.5 bls per ci] But with his motor out 50" and both of our cars had the same front axle weight, which means he was 90 lbs lighter across his rear axle = less traction. It's all about car balance.
We had two sets of 2585's one set on 11" rims, and another with 12". The 12" rims were for running in the finals at Bakersfield, when the sun was down and the track cooling off.
In our car , last time racing I had 9811 rpm @ 186.61, with 4.88 gears and 9000 stall converter, on the 31 tires on 12 rims, last year at the same track [ Sonoma] we ran 190 mph also on the 31's, 4.88, and a 8528 stall converter. So you can see the looser the converter the more slipage.
Feel free to call me if you are looking for more info/ numbers.
Jon Hansen, Hayden wheels, 800-624-3803, 805-444-4489, or jchansen60@gmail.com