Hi Guys. I'm looking for a little information on exhaust pipe size you feel I should be using on my 66 Mustang. It has a 347 Stroker with roller valve train, probably 1986-88 5.0 H.O. block bored and stroked. Forged pistons, crank, etc with 10 to 1 compression. Edelbrock Victor Jr. heads with 1.7 rockers, Comp cams 286H cam with .598 lift/intake and exhaust and duration @ .050 230/230. Shorty headers, Currie Nodular Sportsman rear-end with 3.75 posi. and 15" BFG rear tires.
I've heard people talking about 2" to 3" pipe and advantages to H and X pipe. Any suggestions would really help.
i agree with that guy 3 inch STRAIT PIPESSS i got that on my 00 gt it is sooooo insane, jus watch out for the pigs haha htheyll love you aftr that mod haha
If you go with a pipe that's too large you will loose exhaust gas velocity and any scavenging effect from the cylinders. With your displacement, a 2 1/2" dia. pipe should be about right.
If you are looking to have more bottom end torque, use an "H" pipe crossover. If you want more power at the upper end of your power band, use an "X" pipe. Be aware that the "X" is going to slightly quiet the exhaust sound and make the engine sound more like an exotic import V8.
Dr. Gas, the company first to develop the "X" recommends that the inlet portion of the "X" should match the size of the header's collector and that the outlet end should be smaller by about 1/2". They say that this will promote exhaust scavenging from the exhaust ports on the cylinder heads.
I have an "X" pipe in my exhaust system and it must sound good with my 2 chamber Flowmasters because I've actually had people flag me down to ask what kind of exhaust system I'm using. My 5.0 engine has the Ford Racing B-303 camshaft and it's still pulling at my 6000 RPM redline with the "X".
If you go with a pipe that's too large you will loose exhaust gas velocity and any scavenging effect from the cylinders. With your displacement, a 2 1/2" dia. pipe should be about right.
If you are looking to have more bottom end torque, use an "H" pipe crossover. If you want more power at the upper end of your power band, use an "X" pipe. Be aware that the "X" is going to slightly quiet the exhaust sound and make the engine sound more like an exotic import V8.
Dr. Gas, the company first to develop the "X" recommends that the inlet portion of the "X" should match the size of the header's collector and that the outlet end should be smaller by about 1/2". They say that this will promote exhaust scavenging from the exhaust ports on the cylinder heads.
I have an "X" pipe in my exhaust system and it must sound good with my 2 chamber Flowmasters because I've actually had people flag me down to ask what kind of exhaust system I'm using. My 5.0 engine has the Ford Racing B-303 camshaft and it's still pulling at my 6000 RPM redline with the "X".
Thanks Guys for the response. While I love the noise, I am also concerned about performance. Why build a motor and spend your hard earned cash and then put on an exhaust that detracts from the performance end of the issue? Greek, I know I can always count on you for the answers I'm looking for. I guess I'm looking for the torque since my car basically gets driven on the side streets around here. I'm wondering if the "H" pipe theory is the same with the inlet side equal to the collector and outlet 1/2" smaller? The only exotic import V8 I've ever had was a Porsche 928 and it was muffled down so much you couldn't hear it even at 120 MPH+, so I'm not sure what that would sound like. I guess pretty good if you are getting compliments. I already have the two chamber Flowmasters, but the pipes are small and don't include an "H" or "X" pipe. I also forgot (I believe) to mention the car has a built C-4, so it doesn't have an overdrive gear and rarely gets driven on the freeway, although I would like to start. I'm guessing its going to spin pretty good at freeway speeds.
I think 2.5" would be a good size - I have that with an "H" pipe on my '65, and I am going to do the same on my '66 (mild cam, 4bbl carb, intake, headers)
the 2.5" exhaust (going through the rear valence on my '65) has a good rumble up until about 45 - 50 mph, then is quiet so it doesn't deafen you on the highway - exactly what I wanted.
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I think 2.5" would be a good size - I have that with an "H" pipe on my '65, and I am going to do the same on my '66 (mild cam, 4bbl carb, intake, headers)
the 2.5" exhaust (going through the rear valence on my '65) has a good rumble up until about 45 - 50 mph, then is quiet so it doesn't deafen you on the highway - exactly what I wanted.
Hey Cobra6. What type of mufflers are you running and how many chambers? I think I've decided on the 2.5" pipes like the Greek recommended. I'm wondering if I should run 3" pipes to the "H" and then go back with the 2.5" pipes. What do you think?
i agree with that guy 3 inch STRAIT PIPESSS i got that on my 00 gt it is sooooo insane, jus watch out for the pigs haha htheyll love you aftr that mod haha
hey im a pig and i dont like being called one, but you are right i will love his mod muahhahahahahahahaha
hey im a pig and i dont like being called one, but you are right i will love his mod muahhahahahahahahaha
Well, since you brought it up. I'm a retired cop/pig. I don't really care for the name, but what the hell, been called it a million times. I ended up doing 3" to the "H" and 2.5" back. Sounds awesome and is even louder on the freeway than I like, but it works. The car absolutely rocks now. Just don't try to listen to the stereo. Also had everything mandrel bent. Looks beautiful. The guy that did it is an artist.
Last edited by bubbamace; 09-17-2009 at 08:36 PM.
Reason: More info
Well, since you brought it up. I'm a retired cop/pig. I don't really care for the name, but what the hell, been called it a million times. I ended up doing 3" to the "H" and 2.5" back. Sounds awesome and is even louder on the freeway than I like, but it works. The car absolutely rocks now. Just don't try to listen to the stereo. Also had everything mandrel bent. Looks beautiful. The guy that did it is an artist.
ohh really what department. im currently with los angeles county, even though i use the exhaust as an excuse for a stop i love the sound vrooooooooom.
A 347? Go with the 3", your not going to lose anything. Put a good set of headers on, X-pipe, and 3" out the back or dumped.
Quote:
Originally Posted by The Greek
Dr. Gas, the company first to develop the "X" recommends that the inlet portion of the "X" should match the size of the header's collector and that the outlet end should be smaller by about 1/2". They say that this will promote exhaust scavenging from the exhaust ports on the cylinder heads.
Do you have any tech on this? I have been researching the "X" pipes for a few years, and this is the first I have heard of this???
A 347? Go with the 3", your not going to lose anything. Put a good set of headers on, X-pipe, and 3" out the back or dumped.
Do you have any tech on this? I have been researching the "X" pipes for a few years, and this is the first I have heard of this???
I don't know where The Greek got his information from, but Bob from Allied Mufflers in Bellflower said he read it in an old issue of Hot Rod Magazine. Bob has been in business for 30 years at the same location on Lakewood blvd and also has an online business making exhaust systems for Chargers, Mustangs. big blocks and small blocks for older and newer cars. I've been going to him for years and always get a sweet exhaust system. He was familiar with the "X" equals performance on the high end and "H" system equals torque.
1966 Mustang exhaust pipe size. 
Also had everything mandrel bent. Looks beautiful. The guy that did it is an artist.
