Topic: What is the width from flange to flange on a full size Lincoln disc rear end?

[CadVetteStang]

Am I correct that a full size Lincoln rear end will add 1” of suspension width to each side of a 71-73 Mustang rear suspension? If my information is correct, the 71-73 Stang rear end is 60” wide and the Lincoln is 62” wide.

[Soaring]

Your 73 Mach has a 61.25 axle length, whereas the Lincolns from that era have a 63" axle length.  So, you are correct in thinking that you will need to add nearly an inch to each side. 

[CadVetteStang]

Thank you. You wouldn’t by chance know how much more they weigh do you? My engine makes 550 lbs. torque @ 3,000 RPMs, and I can’t afford a custom 31 spline setup, so I like idea of the Lincoln’s heavy duty rear end housing & axles and the added weight on the rear tires to help with hookup. However, I am worried about the extra unsprung weight that the rear end will add. It will also have stiffer rear springs. I don’t want the car to skate into a drift in autocross and road racing conditions. I’m going to relocate the battery into the trunk to help the body of the car fight tire bounce, but I don’t know if that will be enough to offset the bounce energy that the rear end will generate. What do you think? 

[Soaring]

If you are going to be racing in roundy-round, you might consider a system of stabilizers back there.  You can spend a bunch, or not so much depending on how much you plan to beat on that rear. 

[CadVetteStang]

Autocross 3 to 10 times per year locally; more if I am in the running for regional placement. Each autocross day will cause the engine deliver hundreds of off idle bursts of 500+ lbs. of torque to the rear. Plenty of autocross driving practice (and some drifting practice) in addition to the events. A few trips to the drags to see what numbers it will put up, and entry into any club racing event I can afford to get into that evolves a road course. 

The rear end has a stock Lincoln sway bar on it and is set up for coil and factory four link, but I think the sway bar is too thin and I would convert it to leaf springs. I would keep the factory lower link brackets and rig that into a combination traction bar and left/right pan hard bar.

I’m also looking at a Jag rear end and a C4 Vette rear end. But that’s more dreaming than anything because I just won’t have the money for that much of a conversion. My budget will be spent under the hood and with the front suspension , brakes and wheels.

One thing I like about the Lincoln rear end is the 2.43 gears. That would let me skip the overdrive for now and also allow the majority of the autocross runs to be in first gear creating good engine braking in the turns and 3,000 to 4800 RPM operating engine speeds (550 lb. torque peak to 400 horsepower peak).