Questions regarding C4 to AOD swap.

[69PaleHorse]

Alright, for all you '69'ers out there who have completed this swap, I have a few questions.

1) Will the driveshaft need to be shortened? With all this talk about deals on aluminum driveshafts, now might be a good time to get a new one instead of me shortening the old one if that's what I need to do.

2) I know the swap will require another crossmember/tranny mount. Is this easily fabricated, and if so does anyone have the dimensions?

3) I believe the AOD's have 50 oz flywheels, and the C4 has a 28 oz. I am guessing that there is a flywheel/dampener relationship of sorts because they both have the same weight. If I am correct, will it be required to put a 28 oz flywheel into the AOD? How about the torque converter? Will that need to be replaced or will the old C4 one work?

I'm really just trying to nail down the absolute 'must haves' in order to complete the swap so I know what I am getting into.

As always, thanks in advance for the advice!

 

[68 & 00 GT]

for my 68 I believe it's a 26 oz flywheel. I got a Stall convertor anyway, soI'mnot sure if you can use the C4 one or not. I bet you can. You'll need a shorter / shortend driveshaft, trans. crossmember, and new shifter linkage, and kickdown (TV) linkage.

Should do it. I have all that waiting to install w/ my built AOD, so I'm no expert yet -

 

[allcarfan]

Alright, for all you '69'ers out there who have completed this swap, I have a few questions.

1) Will the driveshaft need to be shortened? With all this talk about deals on aluminum driveshafts, now might be a good time to get a new one instead of me shortening the old one if that's what I need to do.

2) I know the swap will require another crossmember/tranny mount. Is this easily fabricated, and if so does anyone have the dimensions?

3) I believe the AOD's have 50 oz flywheels, and the C4 has a 28 oz. I am guessing that there is a flywheel/dampener relationship of sorts because they both have the same weight. If I am correct, will it be required to put a 28 oz flywheel into the AOD? How about the torque converter? Will that need to be replaced or will the old C4 one work?

1) Im not sure the answer to this one.
2) if you can weld, you can fab one up...or just buy one on ebay
3) You can use your 280z balancer and flexplate on the AOD. You just have to make sure that the bolt patter size on your NEW torque converter (no you cant use your old one from your C4) will fit the converter.

 

[corpse]

driveshaft - I didn't have to shorten it, but I've heard of others having too After it was put back together, I simply jacked up the rearend up and down to make sure everything cleared, and it did.

for linkage..
If you buy an aftermarket shifter and it uses a cable setup, you are half way done. I have a B&M Hammer shifter which is done via cable, which hooked up pretty easy. I still have the hardware linkage here (new stufff) for the shifter to the aod, I use cable so no need (pm if interested).

For the kickdown cable, you can get the lokar one (same one in some kits available), http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=4219&prmenbr=361

The trans x-member I cheated on and got one already made - I forget from where as I bought a kit in the past.

Oh yeah, the AOD yoke for the trans is the same one as the t5. It is said you can use the C4 yoke as long as it's modified, but I wanted a new one anyways.

If you are going to race it, you may want to consider a non-stock valve body, but we'll save that for another post.

 

[DarkBuddha]

1. This is dependent on your swap. I believe there is enough of a difference in the length of the C4 and the AOD to require shortening the driveshaft. I didn't have to in my application, but I went from an FMX to the AOD.

2. I fabricated my own crossmember using a pic of the Windsor-Fox piece as inspiration. I installed the AOD, using a jack stand to support it, then did a bunch of measuring, and made a template using plumber strap. Took the whole thing to my welder and had him weld it up. I got the metal stock from a supply place for free. Total cost: $35 + 4 hours.

3. As I understand it, the flywheel should be balanced to the motor, not the transmission. I just saw this described incorrectly in one of the big magazines. There are only 2 weights of flywheels that are applicable: 28oz or 50oz. I forget which year it changed, but I know early model small blocks were 28oz, while late model motors were the 50oz. The important thing is to get a 164 tooth flywheel with the correct weight. My original was correct and would've worked, but I went ahead and got a new SFI rated piece from NPD for like $45.

Everyone else pretty much covered the other "must haves".

 

[thehueypilot]

A good site to visit would be Lentech and Windsor Fox. The drive shaft was lengthed on my car by one inch. I also took the oppurtunity to remove the damping rubber ring in the driveshaft and replace it with a solid one piece steel tube and spicer u-joints. The front yoke needs to be replaced with a longer T5 unit for better travel distance. The cross member is only $125 from Windsor Fox and works well. I must be the only person that retained my original kick down linkage. When you mount the TV link on the AOD pointing up it will work with the stock kick down linkage. It will provide a one to one ratio which is required by the AOD set up for correct line pressure. My Lentech transmission has about 20k and many hard drag strip launches with no issues. You will need a shift rod kit $58 to use your stock shifter. The flexplate weight needs to match the engines front balancer weight which would be 28 oz if you still have the original engine. A new torque convertor and flex plate $98 will be needed.

 

[allcarfan]

3. As I understand it, the flywheel should be balanced to the motor, not the transmission. I just saw this described incorrectly in one of the big magazines. There are only 2 weights of flywheels that are applicable: 28oz or 50oz. I forget which year it changed, but I know early model small blocks were 28oz, while late model motors were the 50oz. The important thing is to get a 164 tooth flywheel with the correct weight. My original was correct and would've worked, but I went ahead and got a new SFI rated piece from NPD for like $45.

Everyone else pretty much covered the other "must haves".

a 157 tooth cant be used?

 

[jscar1968]

The 28 oz. flywheel must be used to keep the engine in balance. I bought a flywheel with the correct tooth count and weght by going to Kragen and getting a 70 mustang 351 w/ a c6 tranny. That will be the one you need. about 45 bucks. The drive shaft I'm not sure about. On my 66 I had to cut an inch off the end of the input shaft. The driveshaft was the right length, but they have different input shafts. I modified the stock shifter, and an aod linkage and it works alright. Go to darkhorseperformance.com for the t/v cable and if you want to buy a crossmember. Good luck, its well worth the effort.

 

[jscar1968]

AllCarFan, you are correct, the flywheel is to balance the engine, nothing in the trans. A 157 tooth can't be use, it has to be a 164 tooth, like whats on a c6. Don't ask me how I know!

 

[DarkBuddha]

a 157 tooth cant be used?

No, but I'm not quite sure why... starter gear engagement probably...

 

[allcarfan]

hmmmm....

ima have to do some research. Im curious now.

 

[sportsroof351c]

If you use the AOD yoke, you should'nt have to shorten the driveshaft. If you put the AOD yoke and the C4 yoke side to side, the AOD is about an inch shorter, theres you difference. Make sure you get the metal plate that goes between the engine and trans, otherwise the starter wont be in the right place. Use a 164T Flexplate.

 

[bnickel]

the 157T flywheel is smaller in diameter that 164T and all AOD's uses the larger bell for the 164T