Rear Gear Ratio Question with C4

[Bob Gaines]

...OR...You could install the 3.50 rear, then pull out that rare C-4 C-code for safekeeping and install a T5 5-speed. Easy conversion kits out there. That OD 5th gear will give you just what you need on the highway.

This is something I have seriously considered in the past, but was always worried about impacting the original car.  From what I have read, I believe this is a very straight forward conversion and can be done without modifying the car (cutting / welding)?  If I could do this and still get it back to original without too much hassle, then maybe it is worth considering?

As far as impacting the car besides the work needed to do the conversion you have to knock out a metal plug in the firewall for the clutch pedal rod and of course find a clutch pedal, bushing and hardware to add to your automatic pedal support. The manual reverse light harness needs to have a hole put in the tunnel for it because it is different then the auto .

[NC TRACKRAT]

...and you'll need a driveshaft cut to the correct length, a bellhousing, clutch, pressure plate and throw-out bearing and arm with adjuster rod and a 4-speed shift lever. The conversion requires a special transmission support bracket and an adapter plate between the tranny and the bellhousing.  The bellhousing needs a minor mod that any competent machine shop can handle. No metal was cut to install the shifter. It was a fun project!

[shelbydoug]

It's an easy swap but I'd use a 24" top loader if I went to a manual, and I have done that swap. That way the yoke and the driveshaft that you have will swap over. You can put a plug in the punch out if you go back to the automatic.

The speedometer will also hook right up with no changes, but you may need to play with the speedo drive gear to get it to read accurately?

Switching from an automatic to a manual will change the character of the car though, I think for the better?


I had the AOD in my 302 Granada. It's a nice transmission. With it you could leave the 4.11's in with it. 4th gear would be the equivalent of 2.75:1.

With the 4.11s and the AOD, first gear would give you the same acceleration factor as a top loader and 3.89 gears. That isn't shabby.

So it looks like you have some very nice alternatives to choose from?

[98SVT - was 06GT]

..... I pulled the 3.89 and put in 3.00 gears. .... The car got 18 mpg.

A guy gave me a D code 289 for a 65 Fastback I was piecing together. I bottle brush honed it, put in cheap rings and bearings along with the 100,000+ mile HiPo cam from 843. A $25 swap meet Shelby aluminum intake and Holley 600 vac secondary carb. The car had 2.8 gears and fetched 28 mpg on it's inaugural trip to Monterey. I've got to find the pic of the car Kopec sent me with its 14x7 Minilites that SAAC sent out the offer for - if anyone has a set of those (or 15x7) they'd like to part with PM me.

[NC TRACKRAT]

A top loader is a great tranny but it won't give the OP that overdrive 5th gear that the T5 has.

[TA Coupe]

..... I pulled the 3.89 and put in 3.00 gears. .... The car got 18 mpg.

A guy gave me a D code 289 for a 65 Fastback I was piecing together. I bottle brush honed it, put in cheap rings and bearings along with the 100,000+ mile HiPo cam from 843. A $25 swap meet Shelby aluminum intake and Holley 600 vac secondary carb. The car had 2.8 gears and fetched 28 mpg on it's inaugural trip to Monterey. I've got to find the pic of the car Kopec sent me with its 14x7 Minilites that SAAC sent out the offer for - if anyone has a set of those (or 15x7) they'd like to part with PM me.

I believe I have a full set of original lug nuts for the 14x7 minilites if you're interested.

      Roy

[shelbydoug]

A top loader is a great tranny but it won't give the OP that overdrive 5th gear that the T5 has.

Yes, it is a good option but not as bolt in as a T & C is.

Give the man time to digest some of this. I am sure that he feels like an intoxicated giraffe on roller skates stuck in a revolving door? It's all a blur.

[NC TRACKRAT]

  Great verbal visualization!  Suggestion for the OP:  Install the 3:50 gear and see if that does enough for you.  That will put it back to "stock...as delivered" condition. IF you need/want less revs, we've given you some options.

[GeotechDuck]

Give the man time to digest some of this. I am sure that he feels like an intoxicated giraffe on roller skates stuck in a revolving door? It's all a blur.

Hahahaha. 

Going to 3.50s to start.  Manual trans still under consideration.  Thanks for all the information, everyone!!

[98SVT - was 06GT]

I believe I have a full set of original lug nuts for the 14x7 minilites if you're interested.

It shocked me they were aluminum. I was leary but they worked fine.