gear ration of a 1970 442?

shaks 442 clone · April 6th, 2007, 02:59 PM

i recently bought a 12 bolt rearend in a package deal got a gas tank rearend and front disc brake conversion kit for 400 bucks

i was wondering what was the gear ratio of a 1970 442 because i heard they were a limited slip differential and im getting ready to do my rearend i was thinking of 3.55 but i rather go with what the 442 originally had

hope someone can help me out

70Wcars · April 12th, 2007, 08:18 AM

Most common was 3.23 with some 3.42 and as stiff as 3.91 in some 4-speed cars. Remove the cover and divide ring gear teeth number by pinion teeth number to see what you got.

Hope this helps

smcurro · July 11th, 2007, 11:03 AM

An easier way to figure out the ratio is if the axle is a posi turn the axle one full rotation and count the rotation of the pinion. If the differential is open then fix one side of the axle in place and turn the other side two full rotations again counting the rotation of the pinion. If the pinion turns three and a half rotations, your gears are 3.50 to 1. This is much easier than taking things apart.

joe_padavano · July 11th, 2007, 11:13 AM

Quote:

Originally Posted by smcurro

An easier way to figure out the ratio is if the axle is a posi turn the axle one full rotation and count the rotation of the pinion. If the differential is open then fix one side of the axle in place and turn the other side two full rotations again counting the rotation of the pinion. If the pinion turns three and a half rotations, your gears are 3.50 to 1. This is much easier than taking things apart.

Unfortunately, it can sometimes be difficult to tell the difference between 3.23 turns, 3.31 turns. and 3.42 turns. I turn the pinion until the axle shaft turns ten times. It's much easier to tell the difference between 32.3, 33.1, and 34.2, for example.

As for available ratios, it could have been anything between 2.73:1 and 5.00:1.

smcurro · July 11th, 2007, 12:52 PM

You're right, that is a better idea, and then divide by ten. Good thinking!

monzaz · September 4th, 2007, 09:30 AM

Again if you are going to rebuild it you might as well crack it open ...that fluid should be changed after 30 years anyway...lol.

April 6th, 2007, 02:59 PM	#1 (permalink)
shaks 442 clone Senior Member Join Date: Apr 2007 Location: hayward, california Posts: 235	gear ration of a 1970 442? i recently bought a 12 bolt rearend in a package deal got a gas tank rearend and front disc brake conversion kit for 400 bucks i was wondering what was the gear ratio of a 1970 442 because i heard they were a limited slip differential and im getting ready to do my rearend i was thinking of 3.55 but i rather go with what the 442 originally had hope someone can help me out

April 12th, 2007, 08:18 AM	#2 (permalink)
70Wcars Registered User Join Date: Jan 2007 Location: Texas Posts: 64	Most common was 3.23 with some 3.42 and as stiff as 3.91 in some 4-speed cars. Remove the cover and divide ring gear teeth number by pinion teeth number to see what you got. Hope this helps __________________ Dan S 70 442 W-30 4-speed 70 442 W-30 Post Coupe Bracket Race car...10.66 @ 3650lbs.

September 4th, 2007, 09:30 AM	#6 (permalink)
monzaz Registered User Join Date: Jul 2006 Location: Richfield, Oh Posts: 204	IDing rears Again if you are going to rebuild it you might as well crack it open ...that fluid should be changed after 30 years anyway...lol.

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July 11th, 2007, 11:03 AM	#3 (permalink)
smcurro Registered User Join Date: Jul 2007 Location: Belmont, MA Posts: 115	An easier way to figure out the ratio is if the axle is a posi turn the axle one full rotation and count the rotation of the pinion. If the differential is open then fix one side of the axle in place and turn the other side two full rotations again counting the rotation of the pinion. If the pinion turns three and a half rotations, your gears are 3.50 to 1. This is much easier than taking things apart.

July 11th, 2007, 12:52 PM	#5 (permalink)
smcurro Registered User Join Date: Jul 2007 Location: Belmont, MA Posts: 115	You're right, that is a better idea, and then divide by ten. Good thinking!