which gear ratio for 1/4 mile

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440outlawdart

440outlawdart

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i have a 71 dart,maybee weighs 3000lbs,440,727,680 lift cam,31x13 slicks,broke my dana 60,and getting new gears,has 4.56 in now,car ran low 10s with them at about 7200 rpm at the strip,would 4.30s make a differance as im looking to go into the 9s next yaer
 
what are you using for cylinder heads?

Did you buy that car from a guy by the name of Russell...?
 
I have seen cars pick up with higher gears.I gess it would depend on the power band on the cam.if your going threw at 7200 shold drop to around 6800 with a 430. im gessing of corse that depend on what your shifting at.Im shore someone will know more about it.............Artie
 
Just some FYI, I went from 4.30 to 3.73(what I had) and time slips were the same or a 10th or so better. Picked up 2 mph so it was telling me that 4.30's were little too tight for top end.
Was going through the lights at 62-6300 now about 5700. So now I'm thinking 3.91 or 4.10 should get me at 6000 through the lights like my shift point.
 
440outlawdart said:
yea kind of thinking i might pick up on the top end but might loose some at the tree
Click to expand...

now granted this is a different animal but our 528 race hemi in a landy dart clone is in the same range as yours... should be traping around 6800 and is @ 7200...

we tried to have them tighten up the converter more but with no luck... so were going to try 4.10's (from .56's)...

P.S. strange is the only make of 4.30's for a D60...
 
Hi 440outlawdart,

I really find it difficult to believe that your peak rpm is so high. A fellow member recommended 5700-5800 RPM and I agree. I believe this should be your tarket for both shift points and running through the traps. A Hemi car has always been designed to sustain high rpm and the Hemis still have the best head design for flow ever made.

Even a completely stock 440-6pk power plant has 490 ft-lbs of torque right from the factory. Going from 4.56s to 4.30s, I doubt you'll see much difference since MPH and HP are closely related. The suggestion by another member about taking a second look at your converter is a wise thought too, might be too much slipage. Still, another member recommended knowing your HP and torque curves. If the power plant has not been dialed in on a dynamometer, I recommend you do so for next year, it's worth the expense. Then you'll know exactly what RPM to shift at and what your RPM through the traps should be. I wonder whether your carburator CFM is the best choice for your torque curve too.

Hope you reach your goal and best of luck.

T.O.
 
Id go with 4.30s, so when you do go 9s, and you are in that 130-140mph range your RPM will still be in a comfort zone. It is still gonna require more power to get you there though.
 
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