5 speed converson FE Mustang.

[67428GT500]

Well, I will probably pick up a 25 HP with the new heads with the port work 2.20-1.73 exhaust this time. I so that would put me in the 540 neighborhood. Previously it was at 496lb torque all at 5500.  As for the TKO 600 the only thing mentioned was that there needs to be a change in synchronizers if I was planning on shifting regularly above 5500 rpm.

[67xr7cat]

The tko600 has brass syncro rings and they don't like shifting at high rpm. You can get carbon lined syncro rings help that as well as a few other mods. Can also send it to liberty and have it face plated, but that more for race than street.

[blykins]

The blocking rings aren't really the issue.   It's the finish on the gear cones that causes a lot of the problem.  When it's corrected, the finish is corrected, the thrust clearances are blueprinted, and the shift finger is changed.   

They will hold pretty much anything that you can put in front of them. 

[427LX]

Make sure to have the 2-3 shift rail and shifter rail selector finger upgrade if the newer ones don't have it.
Mine got locked up in 3rd gear when trying to go in Reverse and this happened this one time after running it for 12 years.
If it happens you have to pull the trans to get to the middle cover to get it out of gear.

[67xr7cat]

The blocking rings aren't really the issue.   It's the finish on the gear cones that causes a lot of the problem.  When it's corrected, the finish is corrected, the thrust clearances are blueprinted, and the shift finger is changed.   

They will hold pretty much anything that you can put in front of them.

So what kind of finish is recommended? I have a new in the box tko600 from 2006.Was going to upgrade the rings to carbon, but if can use the brass stuff be nice. Thanks, Steve

[427LX]

The blocking rings aren't really the issue.   It's the finish on the gear cones that causes a lot of the problem.  When it's corrected, the finish is corrected, the thrust clearances are blueprinted, and the shift finger is changed.   

They will hold pretty much anything that you can put in front of them.

So what kind of finish is recommended? I have a new in the box tko600 from 2006.Was going to upgrade the rings to carbon, but if can use the brass stuff be nice. Thanks, Steve

Be well worth it to get the shift rail improvement kit and also the synchro upgrade kit from Liberty Gear.

[wowens]

I would call Liberty and ask how much to upgrade the shift mechanism. I've bought three transmissions from them and they work well. I don't like the short throw shifter conversion for the street, much too precise for me. 3rd gear is the weak link, I have shelled two.
Expensive but a good overall transmission.

[Drew Pojedinec]

If all you want is an overdrive, I'd seriously consider the gear vendors.  Nothing wrong with the other paths, but if you are wanting to minimize changes to the car, it seems like a no brainer. 
If you ever wanted to resell the car, just reinstall the tailshaft and original driveshaft, keep the GV

[67428GT500]

I actually liked the GV top loader kit. The problem? 3300.00  For what it is, I thought it pricey. 
                                                                                                   -Keith