This car came equipped with the Ford-o-Matic two-speed automatic transmission. Performance wise it is a hunk of junk. I endured it for a few years but grew tired of not being able to get the meager power my engine produced to the rear wheels in an efficient manner. There where two options at this point: convert to a T-5 five-speed manual, or to a C-4 three-speed automatic. I suppose a C-5 is also an option, but I don't know much about that.
Since both this engine and this car where equipped with C-4s in other configurations, the swap is straightforward. I found that Autozone sells re-manufactured transmissions with three-year warranties for $350 so I ordered one for a 77 Maverick with a 200. It already comes equipped with a torque converter. At the same time I ordered a transmission mount and a Lokar kickdown cable. The only thing lacking was a yoke and the proper length driveshaft.
Not having much experience in this area, I entrusted the swap to Maryland Performance Center who turned it around in a couple of days and for a reasonable price that included not only the swap with the proper yoke and driveshaft cut and balanced, but also a par of custom subframe connectors (click here to read about these). I was fortunate that although they seemed to think my car was goofy at first (A six cylinder! Why?), they ended up really liking it and putting a little extra time into the project to give it a bit of polish.
Phase 2: 8" Rear End
As purchased, the car was outfitted with a 7.25" rear end with 3:50 gearing. This was good for acceleration, especially with the C-4 now having a lower first gear to get me off the line, but a bit revvy at highway speeds. When I got it the rear end was already pretty noisy, and a switch to Redline sythetic fluid didn't help as much as expected. Over time and as the power of the engine increased time it got noisier and noisier. Eventually came the time to rebuild or replace.
The 7.25" rear end is no gem. It's too weak to last very long in a performance application, and rebuild parts are hard to source. On the other hand, the scrapyards are full of them. By this time you have probably figured out that I'm an "why repair when you can upgrade?" kind of guy, so I started researching options.
It boils down to this: 8" or 9". Both have plenty of options in terms of brakes, differentials, gearing, etc. The 9" certainly has wider acceptance in the performance world, but the 8" is lighter and even in stock for is plenty strong for a six cylinder. Also, Mavericks were equipped with a four-lug version that happens to be only 1/4" wider than the Falcon rear end. After quite a bit of shopping on Ebay I found a rebuilt 8" pumpkin with Trac-Lok and 3.25 gearing. Turns out the guy also had a Maverick axle housing with brakes, so I ordered the whole shebang and had a local shop assemble it for me and install it with some Mustang U-bolts and spring plates. This last was necessary as the Falcon springs are narrower than the Mustang and Maverick springs. They also had to once again trim and balance the driveshaft and convert it to the correct rear U-joint as well as install a set of pre-bent brake lines that I sourced from Classic Line.
A Note On Mechanics
I'm no mechanic but I have been working on cars since 1985. I've learned to be meticulous and thoughtful in my work, consider the ramifications of every decision I make, and double check everything. Most car repair is easy if you take the time to understand what you are doing before you begin and then take your time. Most mechanics, however, need to rush because time is money. Further, many modern mechanics are more technician than mechanic. They replace stuff instead of repairing it and to them your car is a job to get through. When faced with a custom job like this, they are easily befuddled and you get results like the following:
- The day after I got the car back my wife took it for a drive and the rear u-joint fell out and dropped the back of the driveshaft into the street. you can imagine the earfull I got for that! I hate to think what would have happened if the front u-joint had fallen out instead...
- One week later I noticed the diff was leaking. Upon closer inspection I saw that the mechanic had removed the breather vent and replaced it with a bolt, causing pressure to build up inside the housing and force the fluid out.
- Shortly thereafter the brakes where sounding funny, so I pulled off a drum and found one of the shoes incorrectly installed.
- A month later a strange clicking sound developed. I couldn't locate it at first, and then one day while I was trolling for a parking space I heard a loud ripping sound and the car died. I looked underneath only to discover fuel puring out of a tron fuel line. The mechanic had dislodged the fuel line and it had wrapped around the driveshaft! Imagine if I had been going 65mph when this happened, or if it had been the adjacent brake line instead of the fuel line.
