Dual Exhaust on single exhaust car this might help

[boxgranch]

I am not sure if some single exhaust cars have the mounting for the hanger for the muffler on both sides, but ours only had the blind holes on the driver's side. I found these at McMaster-Carr:

https://www.mcmaster.com/90187A111/
Tight-Spot hex head screw.

They almost seem to be tailor made for this, but there is a catch, of course. I assumed that the bit that flattens the petals to lock it in place would bite into the petals and stay put. Wrong. What you need to do is tap them for a 3/8" coarse thread bolt. These:

https://smile.amazon.com/dp/B00GX15RRQ?psc=1&ref=ppx_yo2ov_dt_b_product_details
3/8 steel thread cutting screws.

will do the job if you don't have a tap or have already install one and can't get the tap into position. Don't ask. It isn't hard to disassemble one, lock it in a vise, and run a tap or the above screw in and then mount the thing in the hole. It is, well let's say fun and vocabulary expanding if it is on the car.

Bear in mind that the Tight-Spot needs metal at least 1/4" thick to seat and might be happier with more. The sheet metal there falls short, so I put 3 9/16" Grade 8 flat washers under the heads and they seated OK. They will spin when you tighten the 3/8" bolts in place and you have to enlarge the mounting holes on the hanger as it has a hole for a 5/16" fastener.

You could skip this process and just stick the hanger in with the Tight-Spot by itself and it should hold nicely, but I operate on the principle that what goes together will have to come apart sooner or later and my son hopes to keep this car until the thought police pry it from his cold dead fingers because it isn't green enough.

The hardest part of the job was getting the bolt into the one I installed without tapping it first. That and restraining my comments about Ford not putting the threaded fasteners on both sides while my 17-year-old was helping. This car is destroying my good example on vocabulary.

I had considered using safety wire, but I really wanted something more solid.

I am waiting for an obnoxious rattle from the expanders which are now loose in the cavity. I will try to convince my son it makes the car faster.

Luckily, the threaded bit was there for the rear hanger. Someone at Ford probably goofed.

Hope this will help someone. Of course, I am sure someone has a better solution and it would be fun to hear that too. That might help others even more.

​

 

[mjseakan]

Any pics of the finished installation?
Mike

 

[boxgranch]

If I have to crawl under again, I will try to make photos. The NPD dual exhaust kit worked well along with their hangars and fit pretty well to the original exhaust manifolds. The didn't fit on the Edelbrock heads until I ground some metal off the and American Powertrain transmission mount was a major joy to modify so the exhaust would fit.

And so far, no rattle and the exhaust makes a nice noise. Not as loud as my son wants, but will not annoy others or attract LE activity!

 

[Idaho Chris]

I drilled holes and used thread cutting bolts when I converted my single over to dual. Worked well for me.

 

[Bill Kanode]

I am not sure if some single exhaust cars have the mounting for the hanger for the muffler on both sides, but ours only had the blind holes on the driver's side. I found these at McMaster-Carr:

https://www.mcmaster.com/90187A111/
Tight-Spot hex head screw.

They almost seem to be tailor made for this, but there is a catch, of course. I assumed that the bit that flattens the petals to lock it in place would bite into the petals and stay put. Wrong. What you need to do is tap them for a 3/8" coarse thread bolt. These:

https://smile.amazon.com/dp/B00GX15RRQ?psc=1&ref=ppx_yo2ov_dt_b_product_details
3/8 steel thread cutting screws.

will do the job if you don't have a tap or have already install one and can't get the tap into position. Don't ask. It isn't hard to disassemble one, lock it in a vise, and run a tap or the above screw in and then mount the thing in the hole. It is, well let's say fun and vocabulary expanding if it is on the car.

Bear in mind that the Tight-Spot needs metal at least 1/4" thick to seat and might be happier with more. The sheet metal there falls short, so I put 3 9/16" Grade 8 flat washers under the heads and they seated OK. They will spin when you tighten the 3/8" bolts in place and you have to enlarge the mounting holes on the hanger as it has a hole for a 5/16" fastener.

You could skip this process and just stick the hanger in with the Tight-Spot by itself and it should hold nicely, but I operate on the principle that what goes together will have to come apart sooner or later and my son hopes to keep this car until the thought police pry it from his cold dead fingers because it isn't green enough.

The hardest part of the job was getting the bolt into the one I installed without tapping it first. That and restraining my comments about Ford not putting the threaded fasteners on both sides while my 17-year-old was helping. This car is destroying my good example on vocabulary.

I had considered using safety wire, but I really wanted something more solid.

I am waiting for an obnoxious rattle from the expanders which are now loose in the cavity. I will try to convince my son it makes the car faster.

Luckily, the threaded bit was there for the rear hanger. Someone at Ford probably goofed.

Hope this will help someone. Of course, I am sure someone has a better solution and it would be fun to hear that too. That might help others even more.

​

If you want to have enough threads use an item called a "RIVNUT" which comes in most popular sizes and materials. I am using them in many places on my 1971 351C fastback and the installation tools are readily available. I think the popularity of them may have originated in the aircraft industry that uses aluminum in practically all places. I have used them in my 2 Cessna aircraft. I hope that this helps. Thx, Bill

 

[351c1971]

I fabricated a bracket and fished it thru the cross member. Not easy to do, but very strong and close to OEM.