Thread: 8" Ford rear end R&P questions

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With a 3.80 gear to run 70MPH you will be running right at 3,000 RPM, the same calculator sez 2500 RPM @ 70 MPH would be a 3.18 gear. You can pick a ratio from there. I've ran the Auburn posi units in some lighter cars with no problems, fairly sure they have one for an 8". As far as setting in up it's like any other rear end, if you don't have a pinion depth setting tool, probably should farm it out.

John,
I am afraid of lockers in a light car such as a duece. A broken axle means a very quick turn in the opposite direction. If you are not using the car for anything more than fun and crusin' an open differential is all you will ever need and an 8" is tough as well as being cheaper than a 9". A 9" = braggin' rights !! Tho I do have one in my latest - a '57 round back cover.

This is the list of Ford 8" diffs by door post code you can use - remember, pull the axles, drive shaft and nuts on the front of the case and it drops out like a 9", it only weighs less.

OPEN - LOCK - RATIO
2 - K - 2.75
3 - L - 2.79 (What you have)
6 - 0 - 3.00
7 - None - 3.40 (Good choice)
9 - R - 3.25
A - S - 3.50
G - None - 3.55
None - V - 3.91

I hope this looks OK - the preview showed it screwed up - the first letter/number is for open, the second for locker and the last is the ratio.

3.40 and 3.50's are in Granada's and Monarch's. My last 3.40 came from a 77 - 78 Pinto (??) wagon, tho the 4 lug axles were not useable. Standard shift Mavericks had 3.00 and 3.25. Some 6 cyl Torinos had 8"ers as well


Scout out your local junkie

IMO you do not want to run a Locker, but you definitely need to run a Posi. The Posi will give you the best streetable oppurtunity to get your car hooked up to the pavement.


Kitz