Exhaust choices for 69 Mach 1

[afterglow]

I'm restoring my '69 Mach 1 in the Philippines so I try to source locally as much as possible as shipping rates are horrendously expensive.

I'm currently sorting out the design of my exhaust system. It has absolutely nothing to start with so I'm starting with a clean slate. Importing the entire system would be the easiest way to do it but it would also be the most expensive. I've spoken to my exhaust fabricator and while his prices are reasonable and his work is first rate, he has never done a musclecar exhaust yet (mostly Euro exotics & *** tuners). He's asking me what sort of design I'd like and I had very little to say....

What sort of headers should I get (I'm assuming 4-1)? What length of pipes for the headers?? What design?? How about the exhaust?? Straight-through, x-pipe or h-pipe?? If x-pipe or h-pipe, where do they meet? How many resonators?? And how big??

I'm currently using a 351w 4v stock, although I've replaced the original carb/manifold with Holleys....

Any suggestions?? I'm starting from scratch and the price will be pretty much the same regardless of design......btw, this is purely for street use so torque is the priority.....

 

[RogerC62]

Well, personally I prefer long tube headers to the shorty's. They're fairly inexpensive and available through several mustang venders along with Summit and Jegs. After getting those your exhaust fabricator should be able to run pipe back to a decent set of performance mufflers (locally available) then out the back. He can then put a crossover tube between the L & R pipes somewhere upstream of the mufflers at a convenient spot. Fairly simple overall. You could probably find a picture or illustration showing the routing if its that important to look factory.

 

[Sicarius428]

I agree. Some long tubes... preferably Ceramic coated. Hooker headers are pretty nice. H pipe will give you that muscle car sound... an X will give you a more NASCAR sound. There isn't too much of a gain over each other The X will flow better at high rpms... the H will give you better low end torque. It really isn't noticeable in a street car. If you purchase the headers I bet your local exhaust guy can fab up the rest without too much trouble. I had my exhaust shop do a custom exhaust that goes up into the tunnel to get around my sub frame connectors. 2.5 or 3 inch piping should be good and you are set. Tips are all preference. I put dumps on mine but it allows all the exhaust to come up into the cab...
Kevin

 

[69gmachine]

One thing to watch out for on the hooker headers, is they hang a little low. This is usually not a problem unless your car is lowered. My '69 is lowered about 1.5", and I had the 1 3/4" Super Comps. The passenger side was way too close to the ground for my comfort. I replaced them with the Accufab 1 3/4" set which fit incredibly well, but they are a bit pricey compared to off the shelf headers. Other than that, for such a mild engine as you describe, 1 5/8" headers and 2.5" exhaust is plenty big enough, and I'd agree you probably won't notice the difference between an H pipe or an X-pipe on the track much less the street (now if you start building for serious power you might want to reconsider). Put the crossover as close to the headers as practical to get a good pulse on the opposite bank, and not hang down too low. This usually ends up right at the aft end of the tranny in order to tuck up tight. If they're available locally, a pair of Dynomax turbo mufflers will finish it off with a nice sound, and good performance. Otherwise you may have to just take whatever turbo style mufflers they stock.

 

[jerry S]

and I'd agree you probably won't notice the difference between an H pipe or an X-pipe on the track much less the street (now if you start building for serious power you might want to reconsider).

on a serious build, you will definitely notice the difference. I have a 400+ hp engine and really noticed an appreciable pick up in low and mid-range torque by adding an "X" junction to my dual exhaust.

 

[jerry S]

I'm currently sorting out the design of my exhaust system. What sort of headers should I get (I'm assuming 4-1)? What length of pipes for the headers?? What design?? How about the exhaust?? Straight-through, x-pipe or h-pipe?? If x-pipe or h-pipe, where do they meet? How many resonators?? And how big??

Any suggestions?? I'm starting from scratch and the price will be pretty much the same regardless of design......btw, this is purely for street use so torque is the priority.....

Long tube header fitment is always a crap shoot. Some guys with a 1969 Mach 1 drop in long tubes with no fitment issues whatsoever while other guys with a 1969 Mach 1 have to resort to beating their long tubes with a huge iron mallet because their headers are hitting the shock tower (guys like ME, for example).

I originally had a dual exhaust flowing straight out the back. It was loud and boorish. I added an X pipe that really mellowed the exhaust note out. However, I picked up a lot of torque. There is an article in Mustang 5.0 magazine that compared H vs X vs straight pipes on non-catted cars and found that the X pipe made more peak and average torque and HP over the H pipe at all rpms.