I currently have a 4 speed tranny on my 66 atm and iam at the point where the tranny needs to be dropped out and my 289 2v v8 is getting lifted out. Besides the point I have only driven the 4 speed for one summer and I had numerous problems with it. First the linkages from the shifter to the tranny kept seizing up and at one point, had to drive the poor thing to the shop, stuck in 2nd gear cuz the damn things were not lubed and tightened enough. Not to sure exactly on how hard a 4 speed is either on the clutch but it needs to be changed out cuz it is slipping. That was probably cuz of wear and tear though. The guy i bought it off didn't know when it was changed last.
So it brings me to another problem. The outside shell( Shatter Plate or is it the bell housing) Correct me if iam wrong is also cracked, so thats another thing to fix... I checked inside and the everything was intact.
I know with a t5 i will avoid having those linkages so that takes care of one problem.
I'am also in the works of building a 302 and working on a deal to get a stroker kit(331 I believe) for a very good price as well. Iam wondering would that original t4 be able to hold up to the extra 100-150hp I will be giving it.
I also plan on getting a new aluminium Drive shaft to handle the increased torque.
I was talking to one of my mechanic friends and we were thinking that the axle probably needs an upgrade. Atm its gear ratio is 2.80:1 and I believe it is a 8" differential.
I was wondering to how do you determine the size of your diff. I know I may not be the smartest mechanic and for asking such a dumb question but Iam a Electrician haha.

 

The t5 is probably worth it especially since the clutch pedal is ready to go.

I recommend: 1) a hydraulic clutch setup...JamesW can help with parts.
2) decent clutch like the king cobra 10.5 with a matching flywheel (payed about 100 for the flywheel on ebay new and less than 200 for the clutch I think)

Watch out for:

Rear end ratios with the 5 speed a 2:80 will probably be too tall especially if you get the T5 from a 93 mustang cobra with the tall gears and the .63:1 over drive. With this trans a 3:80 is perfect.

2) unless you get a new T5 parts of it will need to be rebuilt that could mean 5 dollars in parts up to about 300. I got mine used for 300.00 I think it may need 1st gear syncros and a new tail shaft bushing.

3) not all t5s are the same if your in it to win it you should stay with the 90-93 t5s those three years only.

good luck

-Gun

 

my fox had a 2.73 rear gear with the t5 it was perfectly fine and free cruising was smooth. but i have 3.55's now and its much more fun around town

 

I'd be careful with a T5 behind a 331. It's very easy to build a stroker that will kill a T5, unless you drive it like a grandma. I have a 331 that's right on the edge of a T5z's 330ft-lb rating (and I still need to put heads on the motor), so I'm going to go with a TKO. More expensive, but it's not something you want to pay for twice.

 

I had a worldclass T5 behind a FRPP 302 crate rated at 340HP and it gernaded one day during a hard launch when I hit 2nd gear. I am going with the TKO in my 66 even though it is more money and more difficult to install.

 

If you drive a lot of highway miles the over drive is nice to have id go for it if you got the money to do it.

 

t5 is WELL worth it, but as already mentioned above any more than 300HP/torque solid, you'll break it sooner or later.

 

Thx for the input guys appreciate it. Yeah I was checking the prices on those TKO's before and had to ask cuz I thought they where a little pricey but like most parts, you get what you pay for. I'am hunting around for a decent tranny right now comparing the prices and hopefully get one for a good deal.
Iam not sure exactly yet how much HP/Torque I will be going for atm, cuz iam still in the works of building up my 331 parts list.
Thx to for the input on the axle, the last thing I want to do is twist the frame on a hard launch. I knew the 2.80:1 wouldn't be able to handle the torque I will be giving it.
Right now everything is in the works, I should probably have a better idea what iam aiming at for Hp/Torque soon its just hard getting enough time to plan it all. With my last year of school approaching I should have more time to sit down and finish my parts list and strip the rest of the old parts out!

 

I am surprised that no one has mentioned this yet. If you got a good deal for your t5, look into upgrading with something like Modern Driveline components. They make t5's pretty freaking strong, and the cost would be less than a TKO. You can even ship them your transmission and have them intall the parts, so you know its done correctly. Plus installation would be a heck of a lot easier too!

 

Modern Driveline doesn't offer G-Force kits anymore, to my knowledge. They ran into a quality control issue with the G-Force kits and decided to stop carrying them.