Slant Six Forum :: 1/4 mile vs. 1/8 mile RPM's

I usually cross the finish at about 6,400.

Most 1/8 mile racers will set the car up with a lot more gear than you run in a 1/4 mile car. If you run 4.10 gears on a 1/4 you might run 5.13 or so on the 1/8.

1/8 is just like 1/4, you want the motor to be turning your target RPM in the lights.

Your motor build will determine what your target RPM is.

If you're only turning 3500 in the 1/8, then you could step up your rear axle gear by 30-40% and top out around 5500.

Lou

Do not build anything based on what Clifford tells you. Those guys do not know their ass from a hole in the ground.

Clifford sells parts. Their recommendation will depend on what they have on the shelf to sell.

Motor RPM will be based on head flow, compression, and camshaft. Decide what you want to build, and gear accordingly.

That car has an 8-3/4 under it, right? Have one set of gears for 1/8 mile and another pig set up for 1/4.

I shift mine at anywhere from 58 to 6400, depending on what I feel like, and how much nitrous I'm spraying.

Author:	Crazy Dart [ Wed Sep 19, 2007 10:13 am ]
Post subject:	1/4 mile vs. 1/8 mile RPM's
Where I live, 90% of the tracks run 1/8 mile. I am curious as to what RPM's you guys turn your slant six's in the 1/8.

Author:	NORM [ Wed Sep 19, 2007 11:36 am ]
Post subject:
I usually cross the finish at about 6,400.

Author:	Crazy Dart [ Wed Sep 19, 2007 11:47 am ]
Post subject:
Quote: I usually cross the finish at about 6,400. 1/8 OR 1/4

Author:	NORM [ Wed Sep 19, 2007 12:50 pm ]
Post subject:
1/4 mile

Author:	slantzilla [ Wed Sep 19, 2007 5:19 pm ]
Post subject:
Most 1/8 mile racers will set the car up with a lot more gear than you run in a 1/4 mile car. If you run 4.10 gears on a 1/4 you might run 5.13 or so on the 1/8. 1/8 is just like 1/4, you want the motor to be turning your target RPM in the lights. Your motor build will determine what your target RPM is.

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Author:	Crazy Dart [ Thu Sep 20, 2007 10:46 am ]
Post subject:
Quote: Most 1/8 mile racers will set the car up with a lot more gear than you run in a 1/4 mile car. If you run 4.10 gears on a 1/4 you might run 5.13 or so on the 1/8. 1/8 is just like 1/4, you want the motor to be turning your target RPM in the lights. Your motor build will determine what your target RPM is. I was kinda wondering what RPM to give me an idea as to how to build the motor. For example, with Clifford's cam the motor only needs to be turned @3500 in the 1/8 per Larry @ Cilfford. However, Erson cam says I can turn it up to 6500. So I am not sure which way to go...

Author:	Dart270 [ Thu Sep 20, 2007 12:55 pm ]
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Most of the RPM ranges quoted from cam manufacturers are a bit high compared to real life on a 225. If you use stock rods and cast pistons, then 5500-6000 is a good redline range. 6000 is pushing it a bit unless your motor is balanced, good rod bolts, nice machine work. With forged pistons, 6200-6500 is OK. With custom rods, 7000 is possible, but hard to make HP up there. Best to aim for a 5500-6000 redline. Almost any cam will start to run out on a 225 above 6000, even with a well ported head. If you're only turning 3500 in the 1/8, then you could step up your rear axle gear by 30-40% and top out around 5500. Lou

Author:	Crazy Dart [ Thu Sep 20, 2007 1:41 pm ]
Post subject:
Quote: If you're only turning 3500 in the 1/8, then you could step up your rear axle gear by 30-40% and top out around 5500. Lou Lou, what I meant was that Clifford only recommended to turn a motor @ 3500 with their cam... I am currently running my car at 5500 with the Mopar Purple Cam.

Author:	slantzilla [ Thu Sep 20, 2007 3:53 pm ]
Post subject:
Do not build anything based on what Clifford tells you. Those guys do not know their ass from a hole in the ground. Clifford sells parts. Their recommendation will depend on what they have on the shelf to sell. Motor RPM will be based on head flow, compression, and camshaft. Decide what you want to build, and gear accordingly. That car has an 8-3/4 under it, right? Have one set of gears for 1/8 mile and another pig set up for 1/4. I shift mine at anywhere from 58 to 6400, depending on what I feel like, and how much nitrous I'm spraying.

Author:	Crazy Dart [ Thu Sep 20, 2007 7:13 pm ]
Post subject:
Quote: Do not build anything based on what Clifford tells you. Those guys do not know their ass from a hole in the ground. Clifford sells parts. Their recommendation will depend on what they have on the shelf to sell. Thats good to know. Quote: Motor RPM will be based on head flow, compression, and camshaft. Decide what you want to build, and gear accordingly. That car has an 8-3/4 under it, right? Have one set of gears for 1/8 mile and another pig set up for 1/4. My goal is 7 seconds in the 1/8. So I need some good stuff. Quote: I shift mine at anywhere from 58 to 6400, depending on what I feel like, and how much nitrous I'm spraying. LOL, I want to achieve 7 seconds on all throttle. What cam do you use?

Author:	slantzilla [ Fri Sep 21, 2007 6:01 am ]
Post subject:
I have a 25 year old Clifford that I bought from Mike Jeffrey used a few years ago. It is .558" lift and 300* advertised duration. It should not work with nitrous, but it does. My car with the good motor has gone 7:48@89 in the 1/8th on a 150 shot, in full street trim.

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