Thought I'd discuss the next 12-14 months

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CZ-75

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My Car
1973 Convertible 351c 2V
OK, so I bought my '73 Vert with a 351C 2V in December, and just got it out of storage last weekend. I realized that the rear end had a bad case of the droops, so I added a rear suspension fix to the list of things I want to do between now and next summer. So here's my list in the order in which I plan to do them:

1) correct the rear suspension. I have 2 new leaf springs, 2 new shackles, 4 new U-Bolts and 2 new I-Bolts. While this is being done, I will verify that I have a 9" rear end (pretty sure I do, but want to be sure before I order new gears for it).

2) Once she has a better stance, I'll re-evaluate the sound coming from the rear end... not sure if it's in the pumpkin (2.75 gears which I'm swapping out anyway), or wheel bearings, but will figure it out after I correct the stance. So, I'll order new gears, bearings, and whatever else I need and get that corrected.

3) Install an Edelbrock Performer Intake, Edelbrock Thunder Series AVS 650 CFM carb, some Ford Racing valve covers, and a generic air cleaner ( I already ahve all of those):D.

4) Replace the FMX transmission with an AOD. This, coupled with a 3.5 or 3.7 rear end should really make a huge difference in performance.

I'd like to get all that done by the end of June, so I can drive it like that for a couple of months so I can determine if I'm happy with the overall performance. If not, then I'll plan engine mods for next winter. If I end up doing engine modes, I'll probably shoot for 10:1 CR and around 400lbs of torque in a nice wide curve.

So here is my question: All of the above is relatively straight forward except for the transmission swap. I have talked to 3 reputable local shops and they are all shying away from doing the work. Is this an omen, or should I keep looking? I mean, you have to worry about input shaft, drive shaft, TV cord, throttle linkage, kick-down linkage.... anything else?

 
You may have to replace the flexplate so the torque converter bolts up. You didn't say anything about a cam upgrade, but you might consider a 2,200 - 2,500 rpm stall converter, just in case. The lock-up torque converter will help with any slippage losses at highway speeds. You'll also need to make sure the AOD is built strong enough. Are you going with the lower 1st/2nd gears that come from the wide ratio version? I believe the crossmember needs to be relocated. One other thing, I believe the detent positions in the AOD and the shift lever and throw lengths are different than the FMX, so you may need to modify your gear shift and also the linkage. The lever on the transmission may also work backwards, and may require going with a shift cable.

Good luck.

 
Looks like you've done your research and have a solid plan, awesome! Concerning the sound coming from the rear end...it may be "normal" especially if you're comparing it with newer cars. There's a certian amount of gear whine that we just have live with.

Jim

 
You may have to replace the flexplate so the torque converter bolts up. You didn't say anything about a cam upgrade, but you might consider a 2,200 - 2,500 rpm stall converter, just in case. The lock-up torque converter will help with any slippage losses at highway speeds. You'll also need to make sure the AOD is built strong enough. Are you going with the lower 1st/2nd gears that come from the wide ratio version? I believe the crossmember needs to be relocated. One other thing, I believe the detent positions in the AOD and the shift lever and throw lengths are different than the FMX, so you may need to modify your gear shift and also the linkage. The lever on the transmission may also work backwards, and may require going with a shift cable.

Good luck.
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Yeah... it is posts like this that make me really nervous. I want to see how it drives with the AOD and a more aggressive rear end gear set before i consider engine mods... but if i do, it will something fairly mild... nothing too dramatic



Looks like you've done your research and have a solid plan, awesome! Concerning the sound coming from the rear end...it may be "normal" especially if you're comparing it with newer cars. There's a certian amount of gear whine that we just have live with.

Jim
Click to expand...

I want to correct the stance and then evaluate. It may just be a noise due to bad geometry... but i think it is something more insidious.

 
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4) Replace the FMX transmission with an AOD. This, coupled with a 3.5 or 3.7 rear end should really make a huge difference in performance.



So here is my question: All of the above is relatively straight forward except for the transmission swap. I have talked to 3 reputable local shops and they are all shying away from doing the work. Is this an omen, or should I keep looking? I mean, you have to worry about input shaft, drive shaft, TV cord, throttle linkage, kick-down linkage.... anything else?
Click to expand...
AOD swap isn't that big of a deal. Here's a thread on how mine has gone - so far... I say that because I still haven't actually fired up the car and gotten my shifter or TV cable completely squared away (on the carb end).

http://www.7173mustangs.com/thread-aod-conversion?highlight=AOD

If you can pull a transmission and put it back in, you can do all of that yourself. Hope this helps.

I'll be updating that thread with some new stuff soon. I decided to dump the stock '89 shifter, cable, and TV cable (I literally got everything with this tranny from the car - '89 5.0 GT) and go with a B&M Megashifter (w/AOD kit) and Lokar TV cable (maybe, since the original TV cable is still good and already properly set-up).



You may have to replace the flexplate so the torque converter bolts up. You didn't say anything about a cam upgrade, but you might consider a 2,200 - 2,500 rpm stall converter, just in case. The lock-up torque converter will help with any slippage losses at highway speeds. You'll also need to make sure the AOD is built strong enough. Are you going with the lower 1st/2nd gears that come from the wide ratio version? I believe the crossmember needs to be relocated. One other thing, I believe the detent positions in the AOD and the shift lever and throw lengths are different than the FMX, so you may need to modify your gear shift and also the linkage. The lever on the transmission may also work backwards, and may require going with a shift cable.

Good luck.
Click to expand...
Hey Don,

Yes, he'll need a 26 oz. flexplate. The P/N for the one I picked up is in my thread above. Along with new flexplate bolts (I had bolts from the AOD, which were too long for my 351C crank - so I snagged some from AutoZone - P/N listed as well).

The original FMX crossmember will work with some trimming (maybe some bolstering as well). The Ron Morris aftermarket bracket is a little big for headers and fits weird (see the pictures in my AOD thread). But the mounting points are fine, as long as the bracket clears the much bigger pan on the AOD.

Everything I've read on the AOD conversion will have the shifter lever flipped over (Summit has a B&M P/N, as well as an B&M AOD kit for their shifters, with the right lever and cable).

 
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You may be running into some reluctance from your local shops due to the fact that converting to an AOD is not plug ' play with a vintage mustang. It will require a certain amount of knowledge of how to go about it and some creativity to solve inevitable issues that will come up. For many shops, time is money and they may not have the confidence to perform the work in a timely manner and for a reasonable cost. Be prepared to talk about this with your mechanics.

Don't forget you will probably need drive shaft work. And a mod to your shifter linkage to line up the detents with your floor shift.

I installed an AOD in my 69 vert in lieu of the original C4. Took me a week or two of messing around in my spare time before I got it right. I started with a new TCI AOD with a Streetfighter 1800 - 1900 stall lock up converter. I installed a Eaton 3.50 Trac Lok rearend setup in my 8" pumpkin. The performance thru the first 3 gears is great and 4th gear results in 1700 rpm at 70 mph. I will admit setting the Lokar cable for the right pressure at idle / shift made me nervous, but I've put approx 1500 miles on it without issue, so it is where it should be.

 
You may be running into some reluctance from your local shops due to the fact that converting to an AOD is not plug ' play with a vintage mustang. It will require a certain amount of knowledge of how to go about it and some creativity to solve inevitable issues that will come up. For many shops, time is money and they may not have the confidence to perform the work in a timely manner and for a reasonable cost. Be prepared to talk about this with your mechanics.
Click to expand...
True dat. There will be some research needing to be done (most of which I've already posted - it's the nit-noids that still need solutions). The neutral safety switch and reverse lock out switch now have options though - depending on preference, they can be wired directly into the AOD, if a harness is provided... or wired into the shifter, depending on the shifter itself. Either way, it'll require some minor electrical work.

The TV cable will require set-up.

The tranny mount will require some adjustment, depending on which one is used.

Exhaust system may become an issue (as did with mine), requiring some fabrication or substitutions.

Etc... etc... etc...

Honestly, it's actually 'little stuff,' in my opinion... but then again, I'm not a shop 'on the clock' attempting this swap, either.

Don't forget you will probably need drive shaft work. And a mod to your shifter linkage to line up the detents with your floor shift.
Click to expand...
Actually, since he has an FMX, and it physically has the same dimensions as an AOD (same gear ratios, too, except with OD), the driveshaft 'should' fit just fine - mine did.

As for the shift detents and shifter indicator, it may or may not be an issue, depending on the shifter in use. Apparently, there's enough space on the stock shifters for 'OD' and 'D' to live in the same area of the gate if the cable is 'adjusted' properly. I remember the automatic shifter in my '82 Mustang was almost identical to the auto shifter in my '71, so I'm thinking if an AOD-equipped 4-eye Fox body ever came with an AOD shifter, that might be the way to go. (This just came to me, and now I'm going to go find out...)

Using the stock AOD shift cable might not be feasible with an early model shifter though, since the early shifters require the cable end bolted onto the shifter lever, rather than a ball-&-socket fastener like the stock AOD cable. I will continue to post what I find in my AOD thread.

 
Exhaust - good point I forgot to mention. The AOD is wider at the bellhousing than any C4 or C6.

Drive shaft - as long as you have enough movement at the slip joint into the tranny. Don't take a chance if you don't have an inch or so of slip.

Sounds like you are on track. Good Luck

 
Exhaust - good point I forgot to mention. The AOD is wider at the bellhousing than any C4 or C6.

Drive shaft - as long as you have enough movement at the slip joint into the tranny. Don't take a chance if you don't have an inch or so of slip.

Sounds like you are on track. Good Luck
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Bill, good points. Did you see the AOD Conversion thread I posted on the other page? Pictures and everything. ;)

The AOD is actually very much like an FMX, but with a monstrous pan and valve body. The exhaust (Hooker Competition Long Tubes) fits... barely... but it fits.

 
Wish you lived closer - I'd do it over the weekend. It's not rocket surgery, after all.

 
As for the shift detents and shifter indicator' date=' it may or may not be an issue, depending on the shifter in use. Apparently, there's enough space on the stock shifters for 'OD' and 'D' to live in the same area of the gate if the cable is 'adjusted' properly. [/quote']
Just a follow-up on my comment: the AOD does not have exactly what would be expected of a modern overdrive transmission. The indicator [used to] read*: P-R-N-OD-D-1... which is essentially the same thing as a standard non-OD transmission (P-R-N-D-2-1). Most 'modern' OD transmissions has P-R-N-OD-D-2-1 (or how ever many gears... you can select the OD mode independently of the final Drive mode)

*I rubbed all the letters off, since my modifications pushed the indicator out of alignment with the letters.

Further reading of AOD functionality, as well as the B&M Megshifter AOD installation instructions, indicates that the Overdrive feature of the AOD is only accessible once final drive is engaged. In other words, there's no OD lock-out (as with more modern OD transmissions, either by a switch, button, or simply selecting 'D' and not 'OD'), or the need to have the 'extra' slot on the gear selector, since the OD won't engage until final drive allows it to.

So, if you're planning on 'slap-shifting' your car (with a stock AOD shifter indicator), you would start in '1', then bump into 'D', then into 'OD,' and from there, the transmission will shift into 'actual overdrive' on its own.

My point: there is no difference between the detents on a stock/non-AOD shifter and the AOD transmission.

As far as my project goes, I'm sticking with the AOD shifter, because I modified it heavily this past weekend. With the right cable set-up (Lokare make nice cables), you could use the stock shifter and nobody would have to know. It would cost me as much to restore my stock shifter (it's THAT bad) as it would just buying an aftermarket shifter, which is why I'll either be sticking with the AOD shifter or look into a B&M product. The stock Mustang auto shifter requires the cable to bolt onto the shifter lever, whereas the AOD has a 'ball-and-socket' mounting solution, hence the reason for a change of cable if you choose to retain the stock Mustang shifter for your car.

Hope that all makes sense.
Click to expand...
 
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It does help. After a few more days fore overnight from shoulder surgery, and I will show all this to my mechanic friend. Maybe he will gain confidence.

 
I completed step 1 today: Rear suspension. We put on new leaf springs and were ready to put on new shocks too. But when we got it up on the lift, we realized the PO already had put new shock, but left the old springs. The old springs were compressed at least 1/16 inch between the U-bolts, and one of the leaf springs was missing the rear most nylon spacer. The springs were beyond shot.

When we put on the new 4-leaf (JLS i think?) springs, which are supposed to be the same specs as OEM, we ended up lifting the rear end by a little more than 2 inches. I was amazed. we went from a droopy rear end to a well balanced lean mean fighting machine.

I have some pics, but it has been a long day, and honestly.. all I want to do is ice my shoulder and have a nice stiff drink or four.

 
New intake manifold and carb were installed last weekend. What a great improvement. The throttle response is amazing.

This weekend, I will be putting new rotors and pads on the front brakes, and will be fixing the parking break, which needed a new front cable.

I also just ordered a Ram Air kit from Don at Ohio Mustang Supply. If any of you have experience with installing one, please share. Originally I was worried about the height of the carb after I swapped In the Edelbrock performer intake and the Edelbrock thunder series carb... But the Edelbrock combination is actually lower than the factory setup, so I may just need a spacer for the carb.

A week or 2 ago, I ordered a wide ratio AOD transmission from Silverfox Performance Transmissions, and have found a local tranny shop willing to do the conversion from the FMX... Just need to order some conversion parts, like Lokar TV cable and an AOD yoke.

I hope to have all this done by Memorial Day weekend.


Forgot to mention my concern about installing the hood plenum... The PO installed classic air cond. system, and the compressor sits really high in the engine compartment...

 
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