Thread: New Gear ?

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Not happy with my 1/4 mile time. I am thinking a new gear could help. Any help.
I have a Detroit locker with a 389 gear.
60 ft. > 1.78
1/4 mile >11.73 @ 119 mph,
Shifting @ 6000 rpms,
28" rear tire.

what are you going thru the lights at rpm wise?

I was gonna ask the same thing, are you winding the last gear out.
What trany? if automatic what stall, what cam? what carb?
For that big block at 6000 rpm's I don't think your far off on the
gearing. I used to run a 410 gear in a dana 60 for the 1/4.
I was turning about 6000 rpm's too, But I had a 4000 stall.
I was turning low 11's but that 71 Charger was about 4200
pounds. What's your weight? 3800.
Are you hooking up or spinning the tires?

I can't say for sure of the rpm going threw the gate, but I will be sure to look next time., but I believe I am at 5500 rpm's.
The tranny is a C-6 reverse shifting.
3800 lbs is correct.
4200 stall
com cam #34-773-9
1050 Dominator
Got some spin, I am working on that too.

TedIII

If you're really at about 5500 through the traps a switch to 4.10:1 will help you... Can also tell by your mph vs ET that you could use some more gear. I would normally suggest a shorter tire since it's easier to change tires than gears unless it's a big change but seeing as how you're already at 28" I donn know if you want to go smaller... A 4.10 should get you a better short time and probably a few tenths off ET. But if you're trapping at 6000 you don't want any more gear

-Chris

Thanks,

Will run again this week, and be sure to check my rpm going threw the lights.
I am thinking a 410 will help but will known more after a few more runs.

You'll need to address your traction problem before worrying about anything else... If you can't hook now you'll never hook with a shorter gear... Good luck with your next runs

-Chris

Ted; I think you just have some tweeking to do.
I love your car, lots of class and style.
I went the ugly light way this time.
Here are some photos of my project.
http://www.flickr.com/photos/kurtvara/page2
Here is my buddies car.
http://loco4fomoco.com/1965_ford_falcon_ranchero.html

im having to go to 5:13's maybe even 5:38's

Originally Posted by vara4

Ted; I think you just have some tweeking to do.
I love your car, lots of class and style.
I went the ugly light way this time.
Here are some photos of my project.
http://www.flickr.com/photos/kurtvara/page2
Here is my buddies car.
http://loco4fomoco.com/1965_ford_falcon_ranchero.html

Looking good and going to be a nice ride I'm sure, your buddies ranchero is hot!

Originally Posted by gassersrule_196

im having to go to 5:13's maybe even 5:38's

Those are some big gears, I personally didn't known you could get them that big!

Originally Posted by skids72

You'll need to address your traction problem before worrying about anything else... If you can't hook now you'll never hook with a shorter gear... Good luck with your next runs

-Chris

Agreed, i am going to adjust the front and rear shocks this week and the caltracs. I hope I get the weight transfer I am looking for.

I've seen your car photo's Ted, Looks like you swapped out the front suspension.
What did you put in there to replace the old one?
I didn't see a sway bar, which is good so it help's the weight transfer
to the back better when you take off.
Are you running slick's or street tires?
Gassersrule is running a sbc 301 which can turn all kinds of RPM's you can get
alot bigger gears then 513. Most big blocks won't take the kind of RPM's the
small blocks do. Your building torque and HP at lower RPM's then he is.
Now I'm just guessing but I'd say he's turning 8,500 RPM's ask him.
That's why he's running that big gear!!!
I'm gonna run a 351 Cleveland in a 2,000 pound car that will only turn about
7,000 RPM's. I'm gonna run inbetween a 4.10 and a 4.56 gear to stay in my RPM range.
See Clevelands like to crack the blocks at 7,500 RPM's, but like your big block they are known for making lots of torque and HP. And we all know torque is what gets you rolling.
Kurt

Installed the mustang II front end kit. I was playing around with the tire pressure, I have slicks on, and I have adjusted the front shocks for 90 10 and I am changing the rear shocks to some 50 50s. According to my dyno sheet, I can run the rpms up to about 6500 without any problems.

A 2000 lb car with a 351, going to be an animal.

I hope so It's taken me long enough.
I just posted some new pictures of some of my progress.
But I have not got the pictures back of the frame in the car yet.
Kurt

http://www.flickr.com/photos/kurtvara/