1966 Differential Swap

Reply Subscribe

Thread Tools

Search this Thread

Jun 16, 2020 | 02:23 PM

fun4evrusa

Thread Starter

Cross-Country

Joined: Dec 2014

Posts: 64

Likes: 0

1966 Differential Swap

I recently replaced my 1966 front suspension with a 2005 Crown Vic Police Interceptor. Now I am thinking about replacing the differential. Would the Crown Vic Diff be an easy swap? What other Diff should I look at that will not change the overall width of the axle.

Thank you, John

Jun 16, 2020 | 09:51 PM

Rusty Fords

Mountain Pass

Joined: Apr 2020

Posts: 106

Likes: 11

I'm not sure on the width of the 66 and not at home to measure mine. On the 57-60's the rear end is narrower and a Ford Explorer is said to work better due to the width issue.

Jun 16, 2020 | 10:28 PM

fun4evrusa

Thread Starter

Cross-Country

Joined: Dec 2014

Posts: 64

Likes: 0

Thank you. I will look into that.

Jun 17, 2020 | 04:27 AM

User 71024

Cargo Master

Joined: Sep 2005

Posts: 2,954

Likes: 64

I'm guessing it's a 9", the best rear end ever built. Why would you want to change it?

Jun 17, 2020 | 04:28 AM

Crop Duster

Logistics Pro

Joined: May 2015

Posts: 4,469

Likes: 964

From: Tri Cities, TN

Wheel track, 65 to 72 = 64.9" front, 60.4" rear. 73 to 79 = 64.9 front, 64.4 rear. The 73 to79 will fit by relocating the spring perches and is actually a better fit under the bed. Don't know what horse power you are making but the stock 9 inch 28 spline will easily handle 400-450 hp in a truck. The 73 and up 31 spline rears are still easy to find in salvage yards if you want something with stouter axles.