515 torque motor vs. 425 transmission

[acgst12]

Hey all--Rookie question. Looking at a 2002 SPF with 460ci cobra jet putting out 535hp/515 lbs-ft torque. Turns out the tranny is a 3550 TKO that is rated for 425 lbs ft. <6k miles on the car. Thoughts on the consequences of this? Assuming the car isn't tracked, does normal driving create more wear and tear on the tranny or shorten the life? Thanks in advance.

[Jim Vander Wal]

Lots of copies of that basic combination running for a long time. The TKO-600 wasn't released until 2004 so there weren't many other options.

The other things to consider are traction and throttle. W/O drag slicks or other sticky tires you'll not get full torque to the road, the tires will be the weak link and slip. And unless you're running full throttle you'll not put out full torque. How often do you expect to have your foot all the way in?

Jim

[1795]

Jim gives good advice. Unless you are running racing tires or possibly Avons, the tires will break loose well before something else does. Besides, how often are you going hammer it that hard and where do you plan on doing that if you are not on the track? Not too many safe situations on the road for that kind of driving, just check on youtube for videos of people getting on it on the street and what happens next.

Be safe and have fun. Unless you are real experienced with a cobra, and even then it can still happen, it will bite you hard if you are not careful.

Jim

[Unique427]

May want to know what the clutch setup is rated for, when it was installed
and model/condition of hydraulic throwout bearing in front of that transmission.
I am assuming a hydraulic throwout since it's a 460 bellhousing and space is likely tight.
"Normal driving" implies lots of stop/go and slipping the clutch on a torque motor like a 460.
Peak torque on that 460 will be around 4500rpm.

If all is good and you don't pound on it...….much...…..it will hold up.

[cycleguy55]

Sticky tires, heavy weight and hard launches are what kills transmissions. Being a Cobra, weight isn't going to be a big factor. Avoid at least one, perhaps both, of the other two and your tranny will last forever.

[patrickt]

Your greatest danger is winning a free half hour on a chassis dyno. If they strap your car down on the rollers, and then nail it in fourth gear, if the output of your engine is greater than your clutch, transmission, or rear can handle then it will make for a very exciting day.

[snakeeyes]

Originally Posted by patrickt

Your greatest danger is winning a free half hour on a chassis dyno. If they strap your car down on the rollers, and then nail it in fourth gear, if the output of your engine is greater than your clutch, transmission, or rear can handle then it will make for a very exciting day.

God, those are painful to watch. It’s amazing how casual people get around dynos. Sitting in the open trunk of the Mustang in the #2 fail?

[acgst12]

Thanks guys—very much appreciate the thoughts and insights. This would be a casual cruiser for me so sounds like it shouldn’t be much of an issue.

[Dwight]

I'll buy the 3550.
I need one for my Fairlane

Dwight

[Anthony]

you should be fine. Maybe an issue if you drag w sticky tires

i think the 3550 is somewhat based off of the toploader. ford initially designed the small spline toploader, which they were putting behind galaxies and 427's. i think they were having issues at the drags, and redesigned the toploader with a thicker input and output shafts to solve the problem. since the cobra is a lot lighter, there will be less stress on holeshots.