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1/4 mile.. what gears do I need to run?

Posted By: hemi4speed

1/4 mile.. what gears do I need to run? - 09/25/12 03:47 PM

I normally just run the 1/8 Mile. I'm headed to a 1/4 mile. My 410 makes peak power at 5800rpm. with 3:91 and 27" tire what Rpm should I be at with my 3:91 at the stripe?

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Posted By: Lil Demon

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 03:55 PM

Nice looking car. Here is a really good calculator for ya:

http://richmondgear.com/112901.html
Posted By: Triple Threat

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 03:55 PM

How fast is the car?

With 3.91's, a 27" tall tire and 6% converter slip. 5825 RPM = 112.88 MPH

Should be good enough for high 11's, if the car is faster than that not a big deal, most cars go across the finish line well above peak HP.
Posted By: hemi4speed

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 04:08 PM

Thanks for the kudos, its mostly street driven but been bringing back to its heritage. It ran a 7:52 @ 93 mph. Its a 4 speed. I just freshen the motor, so I dont know how fast it will go. It dynoed 499 hp/515 trq with a dual plane intake..any predictions?

this is the car back in the day.

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Posted By: Triple Threat

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 04:24 PM

Should run around 11.75 given the 1/8th mile numbers. Probably will cross just barely above your peak. Good looking car!
Posted By: JohnRR

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 04:33 PM

Quote:


this is the car back in the day.



Too bad you didn't put it back like that ...
Posted By: hemi4speed

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 04:44 PM

Close John, all the decals are on magnets and "Purple Haze" should be done this week all Magnetic so I can put them on when I go to the track. Just recently let the original owner take it for spin who race it with a 13:1 340 and 513 gears. Really cool day!
Posted By: Cab_Burge

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 05:38 PM

Quote:

I normally just run the 1/8 Mile. I'm headed to a 1/4 mile. My 410 makes peak power at 5800rpm. with 3:91 and 27" tire what Rpm should I be at with my 3:91 at the stripe?

Ideally you would like to be at peak HP RPM about a hundred feet before the 1/4 mile finish line, maybe a little sooner than that, depending on who you talk to My current car(727 with a 8 inch race converter) gets shifted at or above 7000 RPM in 1st and 2nd gear and crosses the 1/4 mile finish line between 6500 and 7000 RPM,Depending on which set of tires is on the rear( M/T ET Street 13.50x30x15 or M/T 10.5x31x15W slicks) 134.5 MPH on both sets It crosses the finish line in the 1/8 mile at 5900 to 6000 RPM, at 105 MPH iin high gear for less than 2 seconds
Posted By: hemi4speed

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 05:57 PM

Sounds like I wont be changing out the gears Thanks for the help guys!
Posted By: mshred

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 09:39 PM

with 4.10's and a 28" tall tire with the 4 speed, my 365 trapped around 5700rpms, so im thinking you might be close to that as well since your tire is an inch smaller and you have 3.91's.

Also, not sure what tire you are running or how you are going to launch, but you should definitely be doing atleast 11.70's imo...My 3400lb pig ran 11.80's at 116 with horrible 60' foot times- could have had an 11.70 outta it with better hook, but it broke...oh,and my motor was making at most I think 450 at the crank

good luck man!
Posted By: hemi4speed

Re: 1/4 mile.. what gears do I need to run? - 09/25/12 10:29 PM

I'm running BF goodrich Comp drag radials 275/60/15. I may run slicks as I'm being told with a stick car they will absorb the shock more with stiffer side wall..? It pulls nice I'm hoping for mid 11's
Posted By: gch

Re: 1/4 mile.. what gears do I need to run? - 09/26/12 01:59 AM

I would want a softer sidewall with a stick car to absorb the shock and allow it to hook.
If you get too aggressive with the BFG they will likely go up in smoke.
Get them hot nut no need for John Force burnouts with them.Start out easy and bring the rpm launch up 300-500rpm at a time until you get your best 60 ft.
Be prepared to not run the number as 4 speed et's will humble most people w/o a lot of practice.Car should be capable of high 10's/low 11's if it hooks and doesent break.Don't expect it right away though.
Posted By: hemi4speed

Re: 1/4 mile.. what gears do I need to run? - 09/26/12 12:39 PM

Quote:

I would want a softer sidewall with a stick car to absorb the shock and allow it to hook.
If you get too aggressive with the BFG they will likely go up in smoke.
Get them hot nut no need for John Force burnouts with them.Start out easy and bring the rpm launch up 300-500rpm at a time until you get your best 60 ft.
Be prepared to not run the number as 4 speed et's will humble most people w/o a lot of practice.Car should be capable of high 10's/low 11's if it hooks and doesent break.Don't expect it right away though.



Lots of good info thanks alot.. My best 60ft on the BFG was 1.59 and my launch was around 3500. But been having difficulty being consistant and its all been about getting out of the hole. But its way to much fun to change it over to auto.
Posted By: hemi4speed

Re: 1/4 mile.. what gears do I need to run? - 11/10/12 12:31 AM

Just an Update..having alot of fun bringing it back to the way it was in 1970...sure does get alot of looks going down main st..lol!

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Posted By: RoadRunnerJD

Re: 1/4 mile.. what gears do I need to run? - 11/10/12 01:13 AM

Are you running at the track with open headers? If you still get those 60' times, you should expect 11.50-11.70 times. For full race, I would consider a 4.30 rear and 29.5" tires if you could get 6500 rpm's out if it? Otherwise, if you are just going to race it occasionally and drive it on the street, it sounds like you have a good combination.
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