Ford 9 3/8" axle questions splines, ratios, etc.

I have a 1967 Lincoln Continental I am hot rodding. I plan and actually have had someone calculate the power I can get out of my MEL 462 and it was upwards of 436 actual usable horsepower. With that it will have 515 for torque. He computed that I would use a 3.25 posi rear end. This is where I have questions...I found out through research on the net that the 1967 Lincolns had a 31 spline 9 3/8" axle. The original ratio is 2.80 and thats just too high. I wanted either 3.5 or 3.25 and a guy I contacted has both and they are 31 spline. Is the 1967 Lincoln axles the same as the Ford trucks? I know the trucks used 31 spline and not 28. Any recommendations on which ratio to get if I want to cruise the car around the US and also get 14 seconds in the quarter mile (which was calculated after all the mods were punched in). Thanks a lot and I really need to know about the spline count on full size Lincolns in 67.

 

well, i've put a 9 3/8 in a 9" housing before (you gotta notch the housing to clear the ring gear)
sliding a 31 spline 9" pig will be no problem.
14's with a linc?
sounds like fun but you MAY have to drop down to 3.50's or lower to move that tank.
on the other hand, i'm at 5000 ft

 

Yeah...I think a 9" will bolt right in too...but doesn't the 9 3/8 pumpkin use a flange at the driveshaft instead of a yoke? You might need some driveshaft work IF the 9 3/8 flange won't swap to the new setup.
I have no idea...but it might be something you need to check out!

 

Thanks guys. I know the 9 3/8" will swap into a 9" and all you have to do it notch the housing to get it in, but I do not have a 9"!!! I have a 9 3/8"! I think my car should weigh around 5250 alone then add me and a passenger in it and your looking at 5500 so I hope I can get away with 3.25 gears. Will have to think hard about it. I want to cruise a lot so 3.50s are border line not a good street gear. But its a boat so I will think about it. Thanks again

 

I just did this. A 3.50 9" posi out of an 84 Ford van into a Lincoln 9 3/8" housing, bolted right up. both were 31 spline.

 

Thanks a lot and thats some great news! What made you choose that gear ratio??? I was looking into 3.25s for fuel economy but its a huge car so maybe the 3.50s are better??? Thanks a lot.

 

Enjenjo...whats the deal with the driveshaft flange?
Does it just swap over or are only some 9 3/8 setups equipped with a flange instead of a yoke?

 

yes, some have yokes..

 

Like the guy said............find a 9 inch 3rd member of your choice...drop it right in where the 9 3/8 went...........add the correct length 31 spline axles and go.......I build and narrow a lot of 9 inch rearends...we never pass up a 9 3/8s housing...Many of the big T Birds had em also.

M.

 

The flange and yoke will interchange. In my case, the Lincoln housing was no longer in a Lincoln, but it still fit.