gear ratio rr 1974
- Thread starter yannick47
- Start date
jack up the rear end of the car and put it on jack stands and trans in neutral . get under the car and mark one of the rear tires so you can see it. mark the driveshaft also so you can see it.... turn the wheel EXACYLY one time and count how many times the driveshaft turns. thats your rear end ratio.
EXAMPLE: if the driveshaft turns 3 and 1/2 times....your ratio is 3:55
if it turns 3 and 1/4...your ratio is 3:23...and so on and so on......
EXAMPLE: if the driveshaft turns 3 and 1/2 times....your ratio is 3:55
if it turns 3 and 1/4...your ratio is 3:23...and so on and so on......
67 coronet
Well-Known Member
if it is an open rear diff(non posi)you will also need to hold one tire while you turn the other.otherwise you will not get an accurate reading due to spider gear movement.
Garys1969RR
Well-Known Member
On an open rear end, one wheel on the ground, one in the air. Have some one turn the wheel TWO full turns while counting the driveshaft turns. Mine came out to 2 and 3/4 turns. I thought what? 2.75? Well there is also a metal tag attached to one of the housing bolts. It said 2.76! So thats what I've got. But remember on a posi rear, both wheels in air, 1 revolution on tire, while counting the drive shaft turns.
ArtH
Well-Known Member
do i spin the wheel 1ce or twice??i got about 1.7 turns on 1 spin......if its one im getting pissed on..just got a new cam luncati 60303 and the guys down at luncati said 3.23 or higher
1.7 would work out to 1.70 to 1 which is a really high ratio and highly unlikely. Double that, as previously mentioned, and you are at 3.40 : 1 which makes more sense. I don't think too many rears went beyond 2.70 : 1 before front wheel drive came into vogue.
Did you mean Lunati cams?
yannick47
Well-Known Member
yeah just wanted toconfirmon the doublin prt and yes lunati cams
Garys1969RR
Well-Known Member
If you have a posi rearend, you get both tires off the ground. Turn the wheel 1 full turn while counting the # of turns on driveshaft. If not a posi, put 1 wheel in the air , rotate it 2 full turns,and count the driveshaft turns. Post the results and we can tell you the ratio. I am guessing you have a 3.55 ratio. Thats from you saying it went 1.7 turns on 1 tire rotation. I am assuming you had 1 tire in the air, 1 on the ground. With a non posi rearend. So 2 turns equals 3.4 ratio, as Art H said. That would mean 3.23 or 3.55 ratio. As they dont make a 3.4 gear ratio on that one. Good luck.
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