New to Site. Question about McLaren Gear ratio

[falconman]

Hello everyone,

When my father and I did an v6 to v8 EFI swap on his 1985 convertible mustang we used a rear end out of a burnt up McLaren from the local JY. What gear ratios did McLarens come with?

[negusm]

Hello everyone,

When my father and I did an v6 to v8 EFI swap on his 1985 convertible mustang we used a rear end out of a burnt up McLaren from the local JY. What gear ratios did McLarens come with?

What year McLaren? 7.5 or 8.8 rear?

It all really depends. Anything Ford offered is what it could come with.

You really would have to look at the tag on the rear or jack the car up and roll the wheels and watch how much the axle turns.

-Mike

[falconman]

I am not really sure of the year as the car was burnt BAD from 6 inches from the bottom of the doors up. It is an 8.8, I beleive it had the aero front end. I will take a look for the tag.

Do you mean watch how much the Driveshaft turns? what do you count? tire rotation vs driveshaft rotation?

[negusm]

Do you mean watch how much the Driveshaft turns? what do you count? tire rotation vs driveshaft rotation?

Yes, that is what I meant.

I don't know much about the 87+ car but my guess would be its going to be something like a 3.08. The ascMcLarens didn't usually get tall gears.

-Mike

[DaytonaTim]

I know that if it is a posi you can check the ratio directly by turning the driveshaft and counting the turns of the wheels. Both wheels off the ground of coarse.

But doesn't it turn half as much with an open dif. Something sticks in my mind about this...... maybe if both wheels are turning it turns half as much because they are turning in oposite directions. Someone help me on this

[negusm]

I know that if it is a posi you can check the ratio directly by turning the driveshaft and counting the turns of the wheels. Both wheels off the ground of coarse.

But doesn't it turn half as much with an open dif. Something sticks in my mind about this...... maybe if both wheels are turning it turns half as much because they are turning in oposite directions. Someone help me on this

Yes, I just looked this up

For an open diff you need to jack 1 wheel off the ground, spin it 1 rev and multiply the driveshaft revs by 2.

I hope I got that right

For limited slip, you need to jack up both wheels and not multiply by two.

Somebody will chime in I'm sure.

-Mike

[svo413]

From 87 up, the 5.0 got an 8.8 with 2.73 ratio. The 3.08 available as an option. The automatic cars got 3.27 only.