Automatic OD for a 460??

[DocDirk]

After many ankle surgeries and having size 15 footsies I decided on an automatic for my Cobra with a 533 BB Ford engine. Now I'm enjoying cruising at highway speeds with my 2.75 rear differential but the low end suffers.

I'd like to hook up an automatic transmission with OD to this beast so I can put 3.73's in the rear and enjoy the 0-50 as well, but can an AODE or E40D be fitted up to the 460?

The few answers I've gotten from transmission shops and vendors seem to be couched in a frown and an "I would think you'd have to make a lot of changes to your car to do that".

Should i give up on the idea? I would like not to have to revamp the floor, tunnel, etc. to get it done.

Thanks!

Dirk

[xlr8or]

It probably won't require much change to the tunnel area. The real problem is going to be getting one of those OD trans to deal with the torque of that 533 inch motor.

[Karl Bebout]

Dirk, check with fbperformance.com. I'm considering one of their AOD's for my rat powered Cobra. They claim to be able to handle 900+HP.

[FWB]

Originally Posted by Karl Bebout

Dirk, check with fbperformance.com. I'm considering one of their AOD's for my rat powered Cobra. They claim to be able to handle 900+HP.

dirk, thats the trans i have, it will take the torque. they are nice guys call them.

Fred

p.s i have 3:73's i am going to change to 3:50......

[FWB]

some additional info, the C-6 you currently have will rob you of 75 HP to the rear wheels. when the C-6 shifts from 1st to 2nd the drum must completely stop and change direction. the AODE will use far less HP to work. i have drag raced my 468 stroker with FB's trans and it is bullet proof. they will ask some pertinent info for your build and taylor a converter for you. they will even supply the correct speedo gear. the only drawback is the cost of the voodoo fluid they recommend. 112.00 gal. your trans mount will move to the rear about 1.5 inches. the driveshaft will also have to be shortened and balanced. both mods are easy to do. FB will tell you the exact dimensions of difference from your mount to theirs. GO FOR IT! you won't regret it

[DocDirk]

I just got off the phone with Mike at FBperformance, we had a nice long talk about what could be done to change over the C6 to the AOD and he feels that it would work out well to allow me to use 3.73's for low end performance and yet get highway cruising at 22-2300RPM.

I still don't understand the impact of stall speed of the converter on street applications but he's willing to adjust it so even their race converter would give me the behavior I'd like in the lower end response.

Thanks for the lead, this may turn out to be the best thing I've done on this build so far! ..... now to have the parts shipped to the tranny shop and have them do the install so as to avoid the "OMG!!! not again!!" from the sweetest woman in the world

Oh, and why the change from 3.73 to 3.50 Fred?

Regards,

Dirk

[jdean]

Dirk,

With the torque of the 533 and a light car, I would not be looking for high stall on the converter. 2000-2200 should be plenty depending on your cam. It will run cooler and cruise nicely. My 521 (C6) was making close to 500 ft. lbs at 2000 RPM and 580 at 3000, so no need to spin it up for making power to take off.

But I totally agree on getting something with overdrive, and the modified AOD would be my choice vs. the big and heavy E40.

[DocDirk]

Thanks for the replies - this is going to make this car ZOOOOM>.....my idea of a cobra from the beginning! (I wouldn't call my car light as cobras go, probably 2900 - 3000# with driver).

Regards!

Dirk

[FWB]

Dirk,
i found when cruising it was ready to be shifted into OD at 45 or 50 mph. which is the speed limit on most of the secondary roads, so a casual drive, i would be in and out of OD, if traffic slowed or sped up it got to be a pain. OD is actuated with a manual switch. i have a toggle on the dash. but you can put it on the shifter also. the 3:50 gear i feel would put my shift point at a little higher rpm so I would be only using it at a steady cruise above 55 mph. the camshaft will dictate where to be on the converter. i have a 3300 stall and its fine.the FB trans has another feature that takes some getting used to. it free wheels when you let off the gas, like putting in the clutch. i know i was used to the engine slowing the car down a bit while braking.

fred

Originally Posted by jdean

Dirk,

With the torque of the 533 and a light car, I would not be looking for high stall on the converter. 2000-2200 should be plenty depending on your cam. It will run cooler and cruise nicely. My 521 (C6) was making close to 500 ft. lbs at 2000 RPM and 580 at 3000, so no need to spin it up for making power to take off.

But I totally agree on getting something with overdrive, and the modified AOD would be my choice vs. the big and heavy E40.

jdean,
you may not realize that our monsters weigh in at 3300 and 3400 lbs. by no means a light car. we have more frame under us than a mid 60's full size ford.

[jdean]

Yeah, I did'nt notice it was a West Coast....possibly the heaviest Cobra. The 3.73s should help a lot.

[Tom Wells]

Dirk,

What size tires (diameter) do you use?

My car weighs 3100, has a 2.88, 25.7" tires (335/35/17 in the back) with a C-6 and about a 2000 rpm stall converter. Except for the trans running too hot at the track - soon to be fixed with a 1600-1800 rpm mud truck converter - it's a dandy combo.

6000 rpm is 154 mph, at 3000 half that or 77 mph, good hwy cruising speed.

It will blow street tires away at any speed up to about 100 with 46/54 weight distribution if I whack the throttle (try this at the track, please). Track tires stick nicely and don't seem to spin too much under race track conditions.

Rear wheel HP is around 410 after the C-6 gets finished with the engine's output.

It still runs nicely in traffic, idling or even in a really slow parade.

Pretty satisfactory to me for a truck motor

Carl Rossler built the trans and FTI is building the torque converter as I type - at least I hope so...

Regards,

Tom

[DocDirk]

Tom, I respect your experience with the build but I've disliked the experience of cruising at 3000RPM. It leaves the engine quite a bit busier and the exhaust quite a bit more of a nuisance than at, say, 2400 RPM. Do you wear earplugs? I'd sure like to find a less expensive way to get both ends of the stick, but my sweetheart and I plan to put a lot of miles (psssst!! don't tell my ins. agent!) in cruise mode, she thinks 2400 is too loud already and I just want the low end for kicks... will never see the track or be dragged, so it's really not the AGGRESSIVE cobra intention that seems to run in your blood....perhaps the 3.73's will wake mine up!!

Regards and thanks for the input!

Dirk

[A Cobra guy]

Here is another vendor for you. I have only got about 1/2 the horses you do but the trans can take it.
I have had a LenTech in my cobra for over 10 years. the thing has never given me a problem. Like Fred, I have a switch to lock out OD if I want. A nice feature is that you can down shift from 3rd (or OD) to 2nd and it grabs right away. It won't grab 1st until you are going about 10mph but you have plenty of ponies to take care of that.

http://www.lentechautomatics.com/aodproducts.html


Harvey R

[PSB]

I'd stay far away from Lentech if I were you. I had an entire 2 miles on mine before it blew up. Although it had a one-year warranty, it took me longer than a year from the purchase date of the transmission to when I had my Cobra assembled enough to drive. After accusing me of installing the tranny wrong, using the wrong flexplate, not adjusting the TV pressure correctly, etc, it turned out to be a manufacturing defect. They still charged me $1500 (plus shipping - not cheap to Canada) for the rebuild. I now have about 20 miles on the rebuild and I'm having problems again.

JMHO,

Pete