4 into 4 Headers and Side Pipe Modifications

After a couple of years of dealing with my side pipes drooping I made the decision to remove the Shorty Headers / J-Pipes combination and install the FFR 4 into 4 headers, they offer a more secure mount for the side pipes.  In combination with this project I figured I should quiet down the pipes a bit by installing longer mufflers.

I called up Factory Five Racing and purchased a set of their BBK, 4 into 4 headers for the 302 (standard 5.0L).  Right or Wrong, Here is the process I followed to perform the installation and upgrade.

Since I am still running fuel injection I needed to install a set of O2 sensor bungs.  I got this set from JEGS.  I selected pipes 4 & 8 and installed them 12 inches down the pipe from the heads straight up from the bottom (thanks Russ).

Here are the new headers next to the old set-up, notice the flange in the middle of the old set-up.  This gets eliminated with the new headers and offers one less place for a loose connection (droop).

Now I need to Bolt them onto the heads.  Here I got a little creative.  Since the old header bolts kept loosening up and falling out over time, I drilled a small hole through each of the bolt heads so that I can safety wire them in (thanks Carl).

I wired the header bolts in pairs doubling up the wire.

After the header bolts were all tight I checked the fit to the side pipes (not modified yet) and noticed that the new headers were sitting high up in the body cut-outs, so high that I could not fit the side pipes (the drivers side was worse than the passenger side).  I read on the forum that I would need to lower the engine.  This is accomplished by slotting the bolt holes on the motor mounts and sliding them both inward closer to the center of the engine.

Sketched it out

The holes are now slotted (hard to see, Bottom picture).  I also trimmed the skirt a bit for more wiggle room.  After this was done I was able to drop the Engine by about 1/2 inch.  The alignment is now perfect.

Picture of the O2 sensor installed looking up from the bottom of the engine bay.

Any wires that run near the exhaust were covered in Nomex.  Now that the Headers are properly fitted I can move onto the side pipe modifications.

Side Pipe Modifications

I purchased a set of Lobak Mufflers (24″ long) from John at RPM Exhaust in California.  These are about 6″ longer than the stock FFR mufflers and have a steel auger inside.


4004 Dyer Rd.  Livermore Ca.  94551

# 925-606-0198

6″ difference in length.

I cut the old side pipes apart with a hack-saw as shown in the picture, I cut them as close to the welds as possible so that I would have the most amount of pipe to work with.

Check-Out the broken Mount.  In addition to the glass packs having blown out, this crack added to some of the noise.


Some love taps

Next I needed to open up the diameter of the flange on the Lobak pipes.  I used a ball peen hammer and slowly tapped and rotated until the pipe sections fit together.

Now I tested the look

Next I bolted the shorty (cut sections of the side pipes to the newly installed headers and slowly dry fit the other sections.  I used a small jack to hold the alignment as I aligned the assembly and made my marks.

Steve thinks I should just tack the tips on now, Very tempting 🙂

I centered the pipes as best I could.  3 1/2 inch spacing in the front, 4 1/2 spacing in the back.  I was able to use the additional length to get the tips of the pipes as far back as I could without hitting the rear fender.  Next I rotated the tips downward 30 degrees to help aid in sound reduction.

Here is where I needed to look for the cleanest section of the mufflers and make sure that this section was the visible part of the pipes (no seams and such).

I leveled them to the frame of the car and made all of my alignment marks.

Next I disassembled the pipes and using a Dremel tool, ground away the ceramic coating from the weld area.

I started with the Tips, I reassembled the tip back to the previously marked location with the muffler and tested the alignment & straightness by rolling it on the edge of the bench removing all of the wiggle (I needed to use the ball peen hammer again to close up the flange around the tip section making sure to eliminate any gaps.  When it was tight and straight I tack welded them in place with 4 tacks from the MIG welder.  The finish welding will be done by a professional TIG welder.

Tack Welded

The next step is to final weld the mufflers in-place.  This was done using a TIG welder and rotary stand.

Once they were completed I installed them onto the car and aligned the Side Pipe mounts (the brackets under the doors).  I needed to re-align and re-mount these as the original position was no longer valid.  I cut the original (welded tabs) from the original mufflers, cleaned them up and tack welded them into place during a mock installation.  I then finish welded them into their new locations when removed from the car.

I then cleaned up all of the welds and sent the pipes out for coating:

MR Powdercoat – Rich & Matt


Rich stopped by and picked up the pipes and will completely sandblast, coat and polish the pipes.  The finish will resemble polished chrome and hold the heat to 2000 degrees.

Finished Installation

Brackets Repositioned


Published on April 24, 2012 at 9:44 pm  Leave a Comment  

The URI to TrackBack this entry is: https://ffr5355.wordpress.com/ffr-5355-factory-five-cobra/4-into-4-headers-side-pipe-modifications/trackback/

RSS feed for comments on this post.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: