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Discussion Starter #1 (Edited)
I am slowly starting to transform my bone stock 1990 Mustang LX into a street/strip car.

I recently pulled the T5 and swapped in a C4 transmission:

Having plans to take the car to the strip once in awhile, I started looking into what requirements must be met to run slicks. Our local strip is very strict about running a driveshaft loop if slicks are used, so I decided that was the next step.

There are myriads of loops available for the Fox Mustang, but I decided to settle on the Ford Racing loop, which was advertised to have adequate clearance around a Ford Racing aluminum driveshaft.

Getting the loop in, it's actually made by HPM for Ford Racing. It comes in two pieces, with a bag of fasteners.

I began by putting all 4 corners of the car up on ramps so that I could have plenty of room to work.

The loop pieces are bolted together, then the larger cross bar is bolted to the floor pan. The holes that need to be drilled are under the front seats, so the first order of business is to remove the seats.

The seats are held to the floor pan by (4) 15mm bolts. You need to remove the plastic bolt covers to get access to the heads of the bolts.

Once the bolts are removed, disconnect the electrical connectors to the power lumbar supports on the seats.

After that, you have a clear shot to the floor pan.

The next step is to position the upper portion of the driveshaft loop.

The directions say to roll it into place and I found it easiest to just start up at the transmission tailhousing and roll it in that way.

The loop needs to be approximately 4" from the front u-joint. I made a mark on the driveshaft with a Sharpie, about 4" from the rear of the front u-joint, then placed the lower crossbar up and bolted it to the loop. Two 3/8" bolts (use a 9/16 wrench) on each side hold the two pieces together. The directions say to put the nuts on the top for extra exhaust clearance.

The bottom of the floor pan has a few little ridges on the passenger side, and I found it best for the driveshaft loop to actually straddle my 4" mark that I made on the driveshaft. This let the crossbar sit flush against the bottom of the pan.

I measured back from the crossmember on each side to line it up, centered the driveshaft in the loop, and then held the loop in place with jackstands.

I then drilled the 4 holes on each side with a cordless drill motor. Use a 3/8" drill for the holes. I chose to leave the carpet in place instead of removing each door sill and rolling the carpet back. I started on the passenger side, drilled one hole through the pan, then left the drill motor in place with the drill making a carpet teepee. I then took a carpet knife and cut a small 'X' in the carpet, large enough to where I could have access to all 4 holes on each side.

I installed one bolt on each side of the car, run them up tight, then drilled the rest of the holes. Fortunately I was able to reach both the bolt head and the nuts at the same time and just ran them up by myself.

After all the fasteners were tight, I then reinstalled the seats and buttoned everything back up.

Now I'm ready to hit the strip and I won't have to worry about my car taking up pole vaulting.



Stay tuned as the next plan for the Mustang is to install an MSD LED shift light.


25 Posts
Im putting a 398w and a c4 in a 92 fox body that was once a 4 cyl. my question is what driveshaft and other accessories do I need?
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