4.56 or 4.30's

slow96hater

slow96hater

Forum Member
which should i get?? my car see's city cruising, and alot of track. it basically just gets drove to the track anymore. i take backroads. i'm not concerned with how bad a 4.56 or 4.30 will be on the street.


i'm wondering, which will be more benifitial at the track. i am runing a fox body car, with a 306, and a 5 speed. my cam is around 499-510 220. i shift around 6300 rpm. my rear tire size is a 26x11.50 et street.

i am useing 3.73 gears now, and i am tired of going threw the finish line in 3rd gear. the guy i got my motor, and tires from was useing 4.56's with his car, and says he was hitting the end of thr track around 6500 in fourth.

i am leaning towards the 4.30's, but, would love to try out the 4.56's. anyone running this steep of gears, and have any feedback for me?
 
I don't know all of the details of your setup, but......

1. Is your's and his race weights the same or close to it?
2. Is the trans he had the same type of transmission you have?
3. Is the cam is the same one he had?
4. THIS IS THE MOST IMPORTANT detail...Does it pull hard to atleast 6000 RPM?


If you answered "yes" to all of the above, I would put the 4.56's in it and have fun.
 
Whats your mph with the 373's? I less than 100 since you are finishing in 3rd.

IMO I'd stick with the 373's, as you may go slower with a lower gear. The extra shift will kill some ET, and if you arent making alot of power above 6k rpm then you will be out of your power range.

For example, my 347 which should be making ~ 420rwhp, solid roller cam, and 7k redline only calls for a 4.10 gear.

Also remember down the road that if you throw nitrous or a blower on it that 4.30's or 4.56's will def be too much gear and you'll run out 4th, that is unless you go to a 28" tire.

Try to make more power before you change the gears, IMO.
 
joestang said:
Whats your mph with the 373's? I less than 100 since you are finishing in 3rd.
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joestang said:
IMO I'd stick with the 373's, as you may go slower with a lower gear. The extra shift will kill some ET, and if you arent making alot of power above 6k rpm then you will be out of your power range.
Click to expand...

If he is going thru the traps in 3rd gear, why would you think the car would go slower with more gear (this makes no sense, unless he was to put so much in it, say a 5.13, that would cause it to run out of RPM too soon). Also, please explain "a lot of power" with regards to what his engine is making beyond 6K. From the sound of things, this is an N/A setup, and he will need to accelerate as quickly as possible making the most of any and all mechanical advantages.


joestang said:
For example, my 347 which should be making ~ 420rwhp, solid roller cam, and 7k redline only calls for a 4.10 gear.
Click to expand...

Did you use some online calculator for this? Hell, my old 347 making roughly the same power as yours and same shift point as yours, ran like complete $hit with a 4.10 (you did not specifiy a tire so I have to speculate). Change to a 4.88 and it ran like a mofo, picking up .5 seconds and several mph.


joestang said:
Also remember down the road that if you throw nitrous or a blower on it that 4.30's or 4.56's will def be too much gear and you'll run out 4th, that is unless you go to a 28" tire.
Click to expand...

Whether he puts a 28" tall tire on the car or not will have no impact on correcting a gearing issue if he uses a power adder. The gear change will be far to drastic. N/A cars and power adder cars are worlds apart.


joestang said:
Try to make more power before you change the gears, IMO.
Click to expand...

This is my favorite......Yeah, don't try to fix what you have for the cost of a gear change.....Just go make more power! Come on...The guy has a trap RPM issue, and its off by quite a bit, making enough power to make up for it is going to take a good hit of N20, or a bunch of money in heads, cam, intake, pistons, etc.



Here's a vid with 4.10 gears 11.59 @ 117
http://quicklx.com/images/Videos/3rd_pass_off_trailer.WMV

Here's a vid with 4.88 gears 10.90 @123.6
http://quicklx.com/images/Videos/10%5B1%5D.90_pass_8-26-05.WMV

Here's a vid with the same 4.88 gears, WAY more cam (added 500 or RPM), compression, etc....In general more power and more rpm
http://quicklx.com/images/Videos/Milan%2011-3-07%20all.wmv


On all passes the car was launched ~ 200-300 RPM below shift rpm.
 
Manual trans. car you need atleast a 4.30 but I would consider 4.56's

I had 4.30's in my notch with a 600 lift solid roller, pro shifted 5 speed
 
Rob, I believe you could get away with a 4.30 just fine. I don't think you have enough motor for a 4.56. I wouldn't go any higher than a 4.30 with your combo. When I had my silver droptop I had a 4.30 in it and it was just right in the 1/4 with the 5 speed. It was just a little more built than your setup though. If you're dead set on trying a 4.30 or 4.56, go with the 4.30. If you plan on changing to a bigger cam and better set of heads then you might want to go with the 4.56.
 
QuickLX said:
I don't know all of the details of your setup, but......

1. Is your's and his race weights the same or close to it?
2. Is the trans he had the same type of transmission you have?
3. Is the cam is the same one he had?
4. THIS IS THE MOST IMPORTANT detail...Does it pull hard to atleast 6000 RPM?


If you answered "yes" to all of the above, I would put the 4.56's in it and have fun.
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his car was 3100, and my car should be close, or even lighter. he had a world class z trans with the 2.95 first. my trans is the 94-95 trans with the 3.37 first. the motor i am useing, and tires i am useing both came from him in the same car that i got my stuff from. the only different thing i did to this motor is that i put gt40p heads on it. my motor believe it or not does pull to around 6500 to 6800. my car is pulling around 109-112 in the quarter mile right now, if i can use fourth.
 
i'm thinking 4.10's may be my choice because of my 1st gear ratio. i really wasnt even thinking of that till i just said something about my trans in that last post. lol.
 
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my thought exactly paul. i'm just glad i wasnt the only one thinking with my dip stick. lol too bad your name aint jimmy.
 
joestang said:
IMO I'd stick with the 373's, as you may go slower with a lower gear. The extra shift will kill some ET, and if you arent making alot of power above 6k rpm then you will be out of your power range.
Click to expand...

He's right. If anything I would go 4.10s and still keep her only through 3 gears. That 4th gear shift will kill you. I'm guessing your running 12.20-12.40?
 
;1659073 said:
He's right. If anything I would go 4.10s and still keep her only through 3 gears. That 4th gear shift will kill you. I'm guessing your running 12.20-12.40?
Click to expand...


12.43 has been my best. good guess
 
Ok, now knowing that he is actually trapping a ~ 110mph, that is a different story.

If you are NEVER going to make more power then a 4.56 gear will put you in 4th around 6500 rpm at 100mph. With the way MT's tend to "grow" on the top end + the extra speed the gear will give you, I'd say you would end the finish line somewhere between 6500-6800 rpm.

The problem is that if you ever make more power you will have to get taller slicks. You absolutely do not want to have to shift into 5th, and I doubt with a normal hyd setup you will be able to rev much past 6800rpm without valve float.

And quicklx I understand completely what you are saying, but what was your engine setup with those times you got? My guess would be that you had a bigger cam, bigger intake, and needed the extra rpm versus the more "modest" setup that 96hater has?

Also 96hater, what do you mean by "if I can use 4th", what has been stopping you?
 
what i meant by if i can use fourth was, if im far enough away from the finish line to shift to 4th lol. i usually am past the 1000 ft mark (actually more close to what i would think around 12-1250 feet) when i feel i need to shift. lately i have just been letting it dance on the 6800 rev limiter threw the finish line in 3rd. lol. i know its probally not the best idea, but, it helps me by a little bit. my trap speeds in 3rd at the line on the limiter are usually just above 108mph.


i found some 4.10s finally, and am picking them up tomorrow. hopefully they'll be in soon.
 
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