1968 Exhaust system bending my brain...

[dalorzo_f]

Needed to replace the original single exhaust on the C code. Had a "spare" 2" dual exhaust setup from the H pipe back left over from the 390's so figure why not, just buy an H pipe and slap it on as from the H pipe back it is all the same. the duals won't do much for the C code but will work and save me buying a new system...

So I install it. The H pipe sits cockeyed and the RH pipe is just about touching the driveshaft. Fit the rest upto test it out, everything else lines up "ok" but the resonator pipe to H pipe is really tight an will only go on 1".

So I yank it out and take it to a muffler shop. They trim 5mm (1/4") out of the RH manifold connection to square up the H pipe to driveshaft. I also had them expand the hubs on the resonators to slip easily over the H pipe.

Same day service... great. $50 and done...

Get it home put in the H pipe. Perfect fit, even spacing on the driveshaft. :smile:

I then reinstall the rest, both resonators now slip pretty much the full 2" onto the H pipe, where both were 1" before. Cool, no problems makes the fit to the hanger nicer....

Then I go to install the muffler... WTF.... one side is almost 2" further back than the other....

I've tweaked and fiddled, flipped the muffler and it just sits crooked... unsure why as before it fit fine and the movement of the H pipe is a fraction of an inch fore and aft.... the resonators both moved forward about 1".

Anyone got any suggestions, as I'm stumped... walked away this evening and will take a look again tomorrow, but just way weird...

 

[Ruppstang]

Been there done that. Four trips to the muffler shop in one day is why I decided to spend the $$$ and buy the Scott Fuller exhaust for the HCS. Put the whole system on in 35 minuets. It has the original tabs and slots so every things lines up perfectly.
Marty

 

[dalorzo_f]

Yeah, the Fuller stuff is great, used a bit on the EXP repli-bute.

But for a C code a ~$5500 exhaust system (with conversion rate, tax, duty, and shipping) is a bit over the top... if I had a Shelby it would be a no brainer to use his stuff.

The odd part is it all lined up far better before getting the resonators expanded to go on the H pipe... going to tinker with it today and try the muffler every way possible to see if somehow that helps...

 

[Ruppstang]

I bet since it is a C code and did not originally have duel exhaust the hanger studs in the rear floor pans are not drilled in the correct location.

Marty

 

[dalorzo_f]

I thought of that, but they should be very close. I templated them off three '68 dual exhaust cars I have (S convertible, S GT coupe, X code....) while all the holes and panels under the rear seat are not 100% in the exact same spot on the 3, they were within 1/8" or so... and as that would only move the resonators side-to-side, or up/down a bit I can't figure why the fore/aft length is off...

Will tinker today and hopefully get it sorted.

 

[azbeneman]

Do you happen to have the measurements or photos of where you drilled the holes under the rear seats? I am converting a single exhaust car to duals next week and will be going through the same exercise.

Craig

 

[dalorzo_f]

Sorry, no... I used a paper template and tossed it once I was done.... as the reference point seem to shift a bit (due to tolerances on the welding) I can send a photos but the locations are hard to "measure up", thus why I used paper...

 

[dalorzo_f]

And I did get it in, still odd its so tweaked... had to jam on resonator full on the H pie (actually considered trimming the H pipe but did not) and one pulled back about 1". The wrench the muffler into place while clamping to get it "close", still skewed about 1/2" and one exhaust tip is full on, the other half... but clamped in place and looks like it should be OK...

 

[azbeneman]

Any pictures you can send are appreciated. I am the only one of my circle of friends with a 68, let alone a single exhaust that is being converted to duals. It doesn't have to be show car correct (since I didn't go transverse), but I want to be as close to accurate as possible.

I went with the standard Turbo exhaust kit from Virginia Classic Mustang in 2 1/4". It arrived yesterday, but I don't think I will have time to play with it for a week or two. I hope the kit fits reasonable well. It has to be better than the straight pipe glass pack-only dual exhaust set up I cut out of the car when I started to restore it.

Craig

 

[dalorzo_f]

If you are going after market I would suggest aligning the pipes/mufflers and mocking up the system, then determining where the hangers go. assuming the OEM mount points have anything to do with mounting an after market system is suspect as their location is driven by the flange on the resonators.

Many after markets I've seen get installed, wired in place temporarily, then a hanger literally screwed to the floor pan/rear of seat by eye with a drill and tapping screw wherever it needs to go.

Here are a few (bad) shots I have handy... may be able to do a few this weekend. '68 Factory GT S code, Dec '67 San Jose build date.

 

[dalorzo_f]

And a March '68 Dearborn X code... (loved the PO's, "I got a can of house paint to "rust proof" the floors" solution!" :wink

 

[azbeneman]

Thanks for the photos. I should be able to get close to the original spot. I thought about ordering and welding in the doublers, but looking at the brackets, I think they will be sufficient.

I tried fitting the new H pipe yesterday and I was sent the wrong one. I am not happy about it, but will have to waiting until tomorrow to find out what can be done about it.

Craig

 

[dalorzo_f]

It really does not matter that much. As it is after market I'd hang the system before you drill...

http://www.mustangandfords.com/how-to/engine/mump-0707-dual-exhaust-system/photo-gallery/#17

 

[Ruppstang]

It really does not matter that much. As it is after market I'd hang the system before you drill...

http://www.mustangandfords.com/how-to/engine/mump-0707-dual-exhaust-system/photo-gallery/#17

+1 that way you will get just the right height.
Marty

 

[azbeneman]

I finally received the correct H Pipe this week and installed the exhaust yesterday. Overall, the 2 1/4" Turbo kit I ordered from Virginia Mustang worked great and was easy to install.

I got pretty close on the reinforcement brackets. I attached a photo of the finished results. I plan to shorten some of the hanger bracket bolts to clean it up a bit. Thanks for the assistance.