v8, c4, gearing

88mudder · Dec 5, 2007

i need to know what gearing to run on my 302 v8 ranger. Motor has a cam, 4bbl intake and carb with headers. Running a c4 3 speed auto. I am going to be running 33-35" tires. I want the truck to go highway speeds but i dont want the motor to be maxing out at 65 mph. What gear ratio should i run? I dont want the truck to be uberly slow off the line either.

If its not possible, i may have to downsize to 31" tires.

Anybody have any reccomendations?

v-8power · Dec 5, 2007

What RPM range is your cam in?
The way i have always heard to figure gears is you want to be at the RPM your cam "kicks"
in at 55MPH.

For example. If i have a cam that makes power from 2500 to 6500 RPM. I want to be in the 2500 RPM range at 55. Just my .02 though

88mudder · Dec 5, 2007

i dont know anything about the cam, all i kno is its a E303. Anybody have this cam?

v-8power · Dec 5, 2007

Well acording to this website your cam has .220 deg. duration so your cam most likely will be for 1500 to 5000 RPM range. http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=1329

Hjcraver · Dec 5, 2007

E303 Cam Spec.

The Motorsport E303 Cam has peak torque at 2500 RPM and peak HP at 6000 RPM. It has 220 Deg. Duration at .050" lift on both the Intake and exhaust.
35" Tires yields 9 ft. of travel per revolution x 2500RPM = 22,500 ft./ min.
Dividing that figure by 5280ft/ min (using 60 MPH speed producing peak torque) gives a rearend ratio of app. 4.26. Using 55 MPH at peak torque give a ratio of app. 4.65. My recommendation is using around a 4.56 .
Its been a while since I calculated rearend ratios and please feel free to correct any errors my figures may have. Good luck. Hubert

baddad457 · Dec 5, 2007

My Ranger with a Toploader 4 speed turns 2687 @ 60 mph, that's with 3.73's and 28" tires. What ever you figure, you can add a few rpms for the slippage in a C-4. Multiply the tire diameter times Pi (3.1416) to get the circumference. Then divide the circumference into 63360 (inches per mile) to get the tire revolutions per mile, that times the gear ratio gives you the rpms @ 60 MPH. To convert to other speeds, divide or multiply other speeds into 60 to get the conversion factor. Take for instance, what you'd turn at 90 mph, multiply the rpms @ 60 times 1.5. To get rpms at 30, divide by half.

pineypower1186 · Dec 5, 2007

you also have to take into account your torque converter stall speed.

88mudder · Dec 5, 2007

pineypower1186 said:
you also have to take into account your torque converter stall speed.

stock stahl converter out of a foxbody mustang 5.0

88mudder · Dec 5, 2007

sounds like a 4:10 rearend will suit me best for a 35" tire. 2,363 approx rpm @ 60mph sounds about right. Am i correct?

smokeshow83 · Dec 6, 2007

ok these guys with the numbers on the brain my hats off 2 u. now i have a 83 ford ranger with a 2.8 v6 and a 5 speed tranny. it has a 9 inch lift and 35x12.50s. i put 456 gears in it and it hit on the button.has all the power i need and i can pull just about any hill in 5th gear everyday driving and plenty of take off power 2. i didnt have to get it calibrated or anything. i ran side by side with a complete stock truck stock size tires and all i ran the exact speed they were going. now with your 302 and c4 set up i think 410 will be plenty. dont want to go to big cause u only have 3 gears in your tranny.

baddad457 · Dec 7, 2007

smokeshow83 said:
. dont want to go to big cause u only have 3 gears in your tranny.

With the added torque of the V8, you don't NEED the extra 2 gears. :icon_rofl:

Same thing I see with guys who like 13 speeds and run I-10 and south of there in 18 wheelers. (where's the mountains :buttkick:

you bought the 13 speed for? )

Hjcraver · Dec 7, 2007

The E303 cam is a mid-range torque/ strong top end cam and performs better above 2500 Rpm. Ford Motorsport recommends a 5 speed transmission because of the low 1st gear and number of gears. I think a stock 302 Convertor will probably bog the motor a little during takoff trying to turn those 35" Tires. The C4 is fine but I think you need a Stall of around 2500-2600 min.to match the cam. I would love to see your Ranger try to burn some rubber.

COPPERHEAD85 · Dec 7, 2007

alot wil depend on what you are going to do with it..........mud..........crawling......a little of both.......daily driver
creeping around in the woods and blasting thru the gooey stuff.........2 differnt situations
figure out what you really use the truck for the most.

88mudder · Dec 8, 2007

im not using 35" tires anymore...dad dont agree lol. Keeping the 265/70r15's which measured out to about a 27 or 28" tire. I got 3.45 gearing right now, will this ratio be good for street driving?

v-8power · Dec 8, 2007

Yeah your 3.45 gears will work fine. You might want to change them later on though if you do get taller tires.

v8, c4, gearing

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