It is hard to tell because there is not tons of manual swapped crown vic around that broke imput shatf but im sure the mustangs guys at corall.net will have the answer.

in fact it all depends on how you drive the car.

The imput shaft will either twist or brake under hard condition such as drag racing where you give all you got during the launch with sticky tires.
With normal tires if you drop the clutch the tires will burn like hell in no time and will act more or less like a fuse.

When you drop the clutch with sticky tires this is where the stress on the imput shaft is becoming a major problem.

I'm glad with my set-up I didnt brake anything yet as I could have brake the shaft if I would have raced with better stickier tires.
Lucky me the drag radials were not the best with a manual trans so I had no choice to be easy on the launch

input gets abused on the starting line

anyone that had a T5 back in the day knows the input is not always what breaks
in the T5 it was deflection between the main shaft and counter shaft that would move the tooth contact point to the tips of 3rd gear and rip teeth off

I think the story on th tr3650 is that people swap them out and sell them to put in a better transmission which is how I got mine on ebay

the list of internal improvements mentioned in this thread is still pretty short, input shaft.
syncros and shift forks are messed up by the driver and cannot be considered a strength upgrade.
to reduce shift fork damage we have shifter stop bolts, driver skill is the only thing to help syncros (learn to drive/match rpm)
the best mod for drag manual trans is to remove the syncros altogether

x2 if you cant drive no matter what you have you can destroy any manual trans.
this what i like abouth my hurst shifter it has stop bolts so even if you bangs the gears the bolts stop it before you push it too far

What transmissions need spacers for what driveshafts? I know its been mentioned bout the 3650 with a PI shaft but I was unable to find anything on any other trans.

If anyone ever decides to shell out for a 6060 I would recommend the Challenger spec and just get a modular bellhousing. Those gearsets are made to move a 4400# vehicle and will do more for these cars than a Cobra 6060. And it already comes with a 26 spline shaft, stock on Chrysler and GM versions. Only the Ford version uses the 10 spline.

The t-45 is a little shorter that the tr3650.

On a police interceptor the yoke is sticking out of an inch and on my car it's slighly more so that is why i never used the spacer although I have one because the yoke has plenty of contact

I also heard that the steel shafts are longer so would I be safe with the t45 and no spacer or would I be looking for trouble?

I think that the steel shaft is longer than the difference betewen the tr3650 and t-45

on a stock police interceptor with the auto trans you have 1 inch betewen the lip and the yoke.

So you should avoid to have less that that as the travel might not be enought and you will kill the joint if it's the case.

you will have to figure this out when yopu are up to this

That is awesome. Thank you for the info.

just curious how much work would go into installing a manual tranny from my automatic??

@ 2004_p71

You wouldn't happen to have a write up or info on automatic transmissions like you did on manual transmissons??

no the only info I have is abouth the manual trans.
swaping the trans require a more work because you have to install flywheel clutch pressureplate pedals and modify the cross member.
If you are mechanicaly inclined it,s not the end of the world

For the most part yes, but to much work for me...I think it may be easier for me to buy stall converter and call it day.. thanks for the input and AWESOME write up....

thanks man

One more question,So I have been MIA for awhile because I just finihsed college and finally back to my Mercury rebuild. Just how much power (abuse) can our stock tranny's take...would getting a j-mod be sufficient for aftermarket bolt on's. This is what I have and coming soon so far D.S.S. Stage II ported heads, Comp Cam XE278, C&L plenum with 70mm racing throttle body, MZT setup, coming soon; long tubes, under drive pulleys and set of heavier injectors. Don't know how much I will be pushing out but does any know if my stock 99 marquis 4r70w will withstand these changes??

when I mean stock I mean my stock tranny...