There are three choices to make when swapping in a T-5 or Tremec:
Early, Late (5.0) or Aftermarket bell housing.

Regardless of the route taken, there are no necessary modifications required to the car its self. The shifters from both transmissions come up through the original shifter hole!

Note the 2 different Bolt patterns on the Spacer

Bell housing will require some minor modification for the T-5. Because of the different bolt pattern, 4 new holes must be drilled and taped into the back of the housing. A spacer is also required because of the longer input shaft of the 5 speed. This spacer can be used as a templet for the holes. California Pony Cars (CPC) or Sacramento Mustang can modify your current bellhousing or supply one with the necessary modifications if needed.

There are no modifications necessary to the clutch or linkage. However, a new drive shaft yoke is required. CPC sells a T-5 conversion yoke that eliminates the need to shorten the drive shaft, otherwise the drive shaft length must be reduced by 1". Finally, a new cross member is needed. I recommend ordering one from CPC or Dark Horse Performance (DHP).

The Tremec 3550 & Tremec TKO use the same bolt pattern as the original 3 and 4 speeds so there are no necessary modifications to the bellhousing. As with the T-5, the Tremec requires a spacer, yoke and crossmember for the conversion.

The T5 & TREMEC use different crossmembers.

Bellhousing & Spacer Installed

Tremec Installed

Note the larger Yoke for the TKO

A late model bell housing eliminates the need for a spacer between the bell housing and transmission. However, the throwout lever must be relocated with a ¾" spacer inside the bell housing (to offset the longer bell housing). As with the Early housings, a cross member and yoke are necessary to complete the swap (CPC).

Parts Required
Early housing w/T-5

Borg Warner T-5 5 speed
T-5 shifter
Bell Housing drilled for T-5 pattern
Aluminum spacer plate (CPC)
Cross member (CPC)
T-5 Drive shaft yoke (CPC)
Original transmission mount
Original Clutch
Original throwout lever
Original throwout bearing

Late housing w/T-5

Borg Warner T-5 5 speed
T-5 shifter
Late 5.0L Bell Housing
¾" spacer (relocate throwout arm)
Cross member (CPC)
T-5 Drive shaft yoke (CPC)
Original transmission mount
Original Clutch
Original throwout lever
Original throwout bearing

I used an early style Lakewood Scattershield that replaces the original 3 and 4 speed bellhousing. The original aluminum bell housing work great for stock to mild engines. Engines with substantial increases in horsepower should consider the Lakewood for safety purposes.

Another advantage of the Lakewood is the ability to use either tranny without modification. The Lakewood comes with both bolt patterns already and makes life much easier (esp. if you blow up the T-5 and decide that the Tremec should have been in there in the first place, kind of like I did). I've heard the newest Late-model scattershields come with bolt patterns for both trannies and mounts for the throwout lever, the best of both worlds!

Now the bell housing is being replaced by a scattershield... and extreme horsepower is a possibility in the future, you're thinking the 3550 just isn't going to cut it? Then step up to the Tremec TKO. This bad boy needs a 26 spline cluch disc, but that's just straight forward clutch work. Talk to Dark Horse Performance (DHP) for parts. You'll also need a custom driveshaft as the 31 spline yoke requires much larger U-joints than the stock drive shaft can handle. Other than that, it bolts right in the same as the 3550.

Tremec 3550

Tremec 3550 5 speed
Tremec shifter
Tremec cross member (DHP)
Aluminum spacer plate (DHP)
T-5 Drive shaft yoke (CPC)
Original bell housing
Original transmission mount
Original Clutch
Original throwout lever
Original throwout bearing

Tremec TKO

Tremec TKO 5 speed
Tremec shifter
26 spline clutch disc
31 spline drive shaft yoke (DHP)
Tremec cross member (DHP)
Aluminum spacer plate (DHP)
Custom driveshaft
(53" from output shaft to front of yoke)
Original bell housing
Original transmission mount
Original throwout lever
Original throwout bearing