Tremec 3550

[Hg80Design]

I am planning on converting to a Tremec 3550 transmission. Currently I am running a C4 and a 71 302 in my mustang. I already have a clutch pedal installed from my previous transmission.

My question is what exactly is involved in converting my 65 mustang over to a Tremec 3550. I know I will be needing a new crossmember, clutch cable, and a bell-housing. I am trying to do this as cost effectively as possible. So is this a straightforward swap anything I need to be aware of. I have been reading up on this but I figured I would ask yall's advice first.

 

[SnakeStang65]

Having done this in my 65, I can tell you it can be very involved if you want to do it the correct way. There are kits out there that will allow you to put it in, but you will find that the driveline angle is not correct. People on various forums have had good luck with such kits, but I wanted to maintain the 3 degree driveline angle. Most of the kits out there will put your engine around 6 degrees. The way to correct this is to cut the top of the tunnel and raise the back of the transmission up about 1 to 1.5 inches above where the kits will have you mounting the back of the transmission (on my car the rear most top cover plate of the transmission was about 1" above the fomer tunnel at a 3 degree angle of the engine). Then you will have to create your own transmission mount (I actually used a rear cross member from a 93 mustang and made my own mounts) and re-create the top of the transmission tunnel.

Honestly, if you do not need the 3550, I suggest that you go with a t-5. Once again, be aware of the angles again, but the t-5 will not require near the surgery to get it to fit correctly. Also every car is different, so if someone tells you it works for them, it may not necessarily work for you.

For the clutch cable I used a mustangsteve setup and have been very happy with it. Be aware for these setups, if you have headers, they can be an issue.

John

 

[Hack]

I run a 3550 in my Fox Mustang. They are a LOT larger than a T5! It's a tight fit in a Fox.

If you are looking to do things the cheap way, you can use an SROD (I think they came in '79-early '83 Fox Mustangs) 4 speed OD manual trans bellhousing with the 3550.

 

[coolblue65]

I have had my Tremec 3550 installed for 8 years or so using the stock '65 bell housing, stock mechanical linkage, and stock length drive shaft, I used a Dark Horse cross member and shortened input shaft.

I have no issues because of driveline angle (even though it probably is off I have never actually measured).

 

[SnakeStang65]

I have no issues because of driveline angle (even though it probably is off I have never actually measured).

It is actually quite easy if you have your intake manifold off... Take a straight edge and place it front to back on the clean gasket surfaces on the engine block (not the heads even though I guess you could use the valve cover gasket surface if you wanted. I did not since I was using a mockup block when I did mine). Place a degree finder (or digital level) on the straight edge. Record the number. Then take the degree finder and straight edge (if you rocker panel is banged up) and place them on the inside edge of the rocker panel behind the door (near the sill plate or under the sill plate making sure to miss the screw holes) Take this number and subtract it from the number that you recorded above, and that will tell you the angle that the engine and transmission are sitting in reference to the car. Factory measurement is 3 degrees.

Keep in mind that the carb intake flange is not a good reference as various intake manufactures place the carb flange at different angles...

 

[jikelly]

I've got a 3550 in my 73 mustang an do have an issue with the angles. There is more room for the larger transmission in my tunnel, but the top of the transmission is basically resting on it. I need to lower my engine to get the angle right since I can't raise the transmission anymore.

I would like to actually cut my tranny tunnel and make it removable so that if I need to service my 3550 I can pull open its inspection plates without having to remove it from my stang.

You can see my swap on my piss poor webpage. I also rebuilt my 3550 a wile back and made a little guide for that too.

J.K's Mustang Page