Need advice on rear axle for a 428 Galaxie

[nandoz]

I have a 1967 Galaxie 500 with a built 428. I am running a redone C6 with a TCI streetfighter converter. The tranny came from a truck, so it has a lower gear set. My car came from the factory with a 3.00:1 open 9". I need some opinions on a rear end setup. I plan to (have to) use the stock axle housing, drive shaft, and suspension (3 link). I am on an air tight budget, so I don't want to make mistakes. The car is mostly street driven, but I plan on running it at the track. It currently sits on 235/60/15 BFG TA's. I have been thinking about going to a taller and wider tire. What would you recommend for durability in a locker? Gear ratio? tire size? etc. Thanks in advance.

[jayb]

I have a 69 Galaxie with a similar setup.  The tradeoff you face is highway engine speeds vs. performance.  On my Galaxie I ended up with 3.70 gears, which was a good tradeoff in my case.  The car runs mid 14s with that setup, and 2800-3000 RPM at highway speeds.  The tires are 28" tall.

On the differential my first recommendation is always a Detroit locker.  The new ones are nowhere near as loud as the old ones, and they just flat out work.  My Galaxie was put together back in the early 1990s, and I went with a traction-lok differential.  The clutches have long since burned out, so now I leave one streak of rubber instead of two    Should've gone with the locker...

[chris401]

Jay, 265/70/15?

[nandoz]

I was looking at a locker. Do you think the stock axles will hold up? I am running a comp 294s, with the loose converter won't a higher gear like a 3.70 lug it along some?

[jayb]

The stock axles ought to be fine as long as you are running street tires. Are they 28 spline or 31 spline?  31 is better of course. 

Witb the 294S cam you might want to go up to 3.91s, but I don't think that you will notice a problem at highway speeds with the 3.70s.

[nandoz]

I am pretty sure they are 28 spline. I haven't had one out yet, but it came with a 3.00:1 open rear. Is there a way to tell without pulling one?

[jayb]

If I recall correctly on a late '60s Mustang the 28 spline axles have a large rectangular-ish pocket in the center of the axle, on the nub part that pokes through the brake drum.  31 spline axles have two small holes rather than the large pocket.  Don't know if that is the same for other models or not...

[machoneman]

See Kevin's site for 9" and 28/31 spline details:

http://www.kevinstang.com/Ninecase.htm

[Dr Mabuse]

Changing the differential? 31 spline axles are a relatively inexpensive upgrade, well worth the added strength.

[fe66comet]

3.70 is a great all.around gear, just enough to have some power but not to low on the highway. It is basically the final ratio I shoot for when I do a tire change for a truck or Jeep. My big block Nova loved it too.....Jon

[Ford428CJ]

Changing the differential? 31 spline axles are a relatively inexpensive upgrade, well worth the added strength.

True statement! If you dont have 31's in there... Buy a set of new axles and your locker! You wont have a problem with it then. Why take a chance.... JMHO