The Rear Axle is Back!

November 2014

It only took about a week to get the rear axle housing back from the strippers, and in fact the third member was done after only a few days, but it took me about a week after it was done to go down and pick up the differential carrier from South Bay Truck and 4×4.  The owner, Frank Gilliland, really knows his stuff and runs a top-notch, albeit dirty shop.

I knew I needed to change away from the 2.80 gears the Disgustang came with…I can’t imagine how pokey the car was with that rear-end ratio, though the fuel economy was probably decent.  Since I’m going with a Tremec T5 conversion, which has a deep overdrive, I can get away with a higher numeric ratio and probably get even better fuel economy at cruise than the car got back in the day.  After talking with Bruce Couture at Modern Driveline, and getting feedback from a few other guys who’ve done these sorts of conversions, I settled on a 3.55 ratio as being the best option for getting a good balance of performance and economy.  But once I walked into Frank’s shop, that’s where things went sideways a bit.  And by sideways, I mean over budget.

The good guys, like Frank, prefer to tailor their approach to your goal rather than to build to numbers.  His first question for me was, “how are you going to use the car?”  I told him I planned to drive it on the street, that I was going with a stock-plus configuration, 4-barrel carburetor, 289, T5 conversion, etc.  He recommended a 3.55 ratio as well, but he went a little further.  “Do you think you’re going to do any burn outs with it?”  My blood warmed…I smiled…”Maybe.”  Frank then recommended I look into putting some sort of limited slip differential in, as long as I was changing gears, now would be the time to do it.  I took the bait and went with his recommendation of doing a Detroit TrueTrac, which will limit wheel spin but won’t crack every time I go around a corner like the old “lockers” did.  I’ve been running pretty true to budget so far, but adding a limited slip diff is an extra $700 I hadn’t planned on.  Hopefully this isn’t the beginning of a trend.

We’ll see how it drives eventually, but that’s still a long way off.  For now, the order of business is to paint and reassemble the rear axle, which as you can see from the pictures below, I’m well on my way to doing!

Note: This is a status update post to catch readers up from my 18-month posting hiatus.  For simplicity, this entry is written as if it had just recently occurred, however it actually happened in November 2014, as noted above.