rear axle ratio

[karolscali]

hi people what would you recomend for gear axle ratio? mine has the 2.79 right now. i have a 302 mild cam headers 4 bbl auto. i just want some more off the line, but i would still cruise a little on the hwy. i was thinking of 3.25ratio, would that be a good all round ratio? also i was looking at dynamat for floor insulation, or just the traditional good enough? thanx roland

 

[rvrtrash]

Mine has a 3.00 and I get second gear chirps at about 3/4 throttle (302-4V, probably a bit more radical cam, automatic w/shift kit). It cruises well on the highway also. A 3.25 will get off the line better but run at higher RPM's on the highway. Everything is a trade-off. You just have to decide what you want more.

Steve

 

[PNewitt]

It depends on what the price of gas means to you....

A 2.79 will give you about 18-22 mpg. A 3.25 will probably give you about 18mpg and less.

At freeway speeds, if you downshift at 55, you'll be glad you have the lower ratio (2.79) with the torque of a hipo motor to pull you up to 75 (or so, not to advocate speeding..) with the power without the engine screaming, if it were a 3.25. It's like my '94 GT. It's a 3.25, with the overdrive (with a pushbutton for OD or not), and I can choose. What a difference!

If Oil hits $100-150 a barrel by Spring, we're all in trouble.

Paul N.

 

[rvrtrash]

It depends on what the price of gas means to you....

Paul N.

Absolutely nothing! I don't use my "older" cars as daily drivers so when I do drive them it's about enjoyment, not economy, otherwise I'd be driving a hybrid at 30 mph in the left lane of the freeway and munching organic celery sticks. With 5 eco-unfriendly classics and a 3/4 ton diesel I have a carbon footprint bigger than Al Gore's house. :grin:

Steve (I'm rvrtrash and that's my excuse! )

 

[PNewitt]

Well, yeah, if it's just a car for a pleasure drive, or off to a car show, the price of gas means nothing.

But for those that may drive their GT/CS a lot (like me, I have 430K miles on mine since 1974); you'll want to be a bit more frugal. I know of several CS owners that drive theirs a lot, like to work, vacations, etc. I remember whining when gas hit $1 a gallon!!

I like the idea of hybrids...since it will extend our availibility of gas for the cars we like. More than once, I've been passed by a Prius at 80mph, weaving through traffic!! One time, I was passed by a test Hydrogen powered Focus in Sacramento the other day, at 90mph! We gave each other thumbs up!! It was nuts!!

Paul N.

 

[robert campbell]

Steve,
License plate frame on my fastback says. "There is more to life than gas mileage". 2 cars that get "gallons to mile" not "miles to gallon". GT/CS is just a bit better. 12 to 14 range on a good day. "Puddin" (won't pull the skin off a cup of pudding) my 96 3.0 Ranger 4X4 is my economy driver. 18 to 22 on a good day.

Live 10 minutes from work and carpool or sometimes ride the bus. Like Steve, I drive mine alot but not far and all about the fun. So not to much carbon goes up in smoke!

Gas prices are a pain, but they don't stop me.

Back to the thread. The best choice is an AOD and 3.5 or 3.7 gears. I have a gear vendors overdrive in my 57 wagon with 3.7's! Works great! Or be like me in my Fastback. Currently 4.11's with a wide ratio top loader crash box. I am considering 4.30's. Bit busy at 55, but oh baby, do I get there quick!!!

By the way if you start playing with tires and wheels and drop your tire diameter a couple of inches, that will lower you gear ratio a bunch. Not sure what your thoughts are on your tires.

Celery is great if you have enough peanut butter!!!

Rob

 

[joedls]

Steve,
The best choice is an AOD and 3.5 or 3.7 gears.
Rob

My car had an AOD with 3.50 gears. It also had 28" diameter tires, which acted like higher gears. I was told I should be able to get somewhere around 18 MPG on the highway if I kept my foot out of it. Never was able to find out. The best I ever got was 13. :grin:

 

[robert campbell]

Joe,
I have a similar problem... Heavy-a-footest-itis!!! Took my Weber inducted Fasback to Long Beach Washington for a car show. Couple hundered miles. Tried to really baby it!!! Could not get there on one tank....

The results. 7 miles to the gallon.... Now that is a carbon footprint for a car!!! Fortunately, I drive it about 500 miles on a good year.....

Rob

 

[joedls]

Joe,
I have a similar problem... Heavy-a-footest-itis!!! Took my Weber inducted Fasback to Long Beach Washington for a car show. Couple hundered miles. Tried to really baby it!!! Could not get there on one tank....

The results. 7 miles to the gallon.... Now that is a carbon footprint for a car!!! Fortunately, I drive it about 500 miles on a good year.....

Rob

I did better than that, but I usually got 8-10.

 

[Midnight Special]

hi people what would you recomend for gear axle ratio? mine has the 2.79 right now. i have a 302 mild cam headers 4 bbl auto. i just want some more off the line, but i would still cruise a little on the hwy. i was thinking of 3.25ratio, would that be a good all round ratio? also i was looking at dynamat for floor insulation, or just the traditional good enough? thanx roland

...My J-code 302/ 4v has the factory 3.00 ratio. Plenty of "go" off the line, yet comfortable @ 70 mph. 'Gets about 13/18 mpg.

Both 390s have 3.25 and go like hell out of the chute, but like to cruise around 55/60 mph @ 8/10 mpg. (4/6 when Don drove it)

The C-code has a 2.79 and gets around 18/22 mpg and tho not as peppy, will cruise all day at 75 mph.

The black 302, 4v/ 4-speed has a 3.18 posi and is quick as well as nice highway cruiser. That's all I can tell you 'cuz the speedo/ odometer runs backwards ;-)

 

[franklinair]

I suggest keep it simple. A J code 4/v with a 3.00 will do just fine. Ford thought so, too!
Neil

 

[di81977]

I have 3.55's with a C4 auto. I don't drive it very much other than to shows and to drag race. I would not go any more than 3.25 if you will be doing much freeway driving.

I agree the ideal set up would be an AOD.

david

 

[franklinair]

I agree the AOD's are nice. Things to consider are price of the tranny, installation cost, you must add an oil cooler, I think a different cross member also. What type/how much driving per year are you contemplating? All these points led me to opt to retain the C-4 A/T and the 3.00 rear.
Neil

 

[nates68]

my J-code 302 has 355 gears,4-speed runs fine 70 @3000rpm,around 18mpg , I wouldnt go any higher. nates68