Big Block 427 Exhuast set up question

EIGHTEIGHT_GT · Aug 15, 2005

My father is rebuilding a 427 that was out of the 67 Shelby GT500 that he sold(god knows why) like 20 years ago. My question is what exhaust/ muffler system should he get? He has old glass packs right now but I told him those have to go. The motor is stroked and bored almost to a 454. 308 duration cam. 10.2 to 1.About a 510 horse motor when done. This thing will sound so bad ass I cant wait. My question is is there anything that will sound bad besides flowmaster? I will use them but only If I dont find anything else. I told him atleast 3 inch all the way through. The flows will sound awesome with that big cam and driving but will it scare the women and children when he mashes it? Insight PLEASE!

iskwezm · Aug 15, 2005

the cam really isnt that big for that size engine,if it was a small block it would sound a lot nastier,but should sound good.I would say try the Spin Techs or Borla,i dont care for the sound of Magnaflow

70vert · Aug 15, 2005

what are you gonna put that thing in?

don't know about the exhaust, but you might want to browse cobraautomotive.com for tips and parts on that engine. They're dedicated to vintage racing and claim that they're engine people first and foremost. You've basically got the ultimate vintage race engine there. You should find out where the Shelby it came from ended up - cha ching!

65up2d8 · Aug 15, 2005

It probably wasn't the original engine in the Shelby, although I agree that it is still a valuable engine. The ultimate value would depend on what type of 427 you have, whether it a low-riser, medium-riser, side-oiler, etc. Although I'm certainly not claiming to be a 427 FE guru here, from what I've read there were several different configurations of the engine that varied in availabilty and potency. The reason that I say the motor is likely not original is that, although the exact number of Super Snakes (a G.T. 500 with a 427) produced is not known, the consensus is that no more than 50 were ever made, and the number of original survivors can be counted on one hand. Regardless, it is still a very cool engine that has a lot of performance potential.

D.Hearne · Aug 16, 2005

Why do people equate "LOUD with "fast"? Put a set of quiet mufflers and enjoy the sound of those two 4 bbl carbs ( it DOES have two fours, doesn't it?) Also, 2 1/2" exhaust is PLENTY big, 3" is just plain a pain in the butt to deal with in a classic, not to mention expensive.

chepsk8 · Aug 16, 2005

I had Turbo-Style Mufflers on the 428. Nice rumble at idle, and decent on the highway. When you got on it, plenty of authorative noise to let everyone knoe you're packing big cubes.

I had 2 1/2 exhaust with headers, I thought it was a super system.

1320stang · Aug 16, 2005

Another place to go for FE info (330,352,360,390,406,410,427,428, did I leave one out David?) is the FordFE.com website. The guys on there have all different styled cars (and there are some Shelby owners, but their main focus is the FE engine. I agree with David on the size and loudness of an exhaust. To me, free flowing is more important, but you need some back pressure. I'd just as soon in be quiet as possible.

I remember a post on the FE forum about a company that was making exhausts for old Fords, I think the name "Pypes" was in there somewhere....

70vert · Aug 16, 2005

links at your service

here's the Pypes:

http://www.pypesexhaust.com/

EIGHTEIGHT_GT · Aug 16, 2005

Motor

The motor came in the Shelby when my father bought it but it was not the original. The original motor was a 428. This 427 came out of a 63 1/2 galaxie by the guy that my father bought the car from. He does have the original dual quad intake AND carbs for the 427. Apparently the rear one is quite rare. He also has a tri-power set up for it. He will be using a predator for it believe.The motor will sound fine. I dont know why you dont think that cam is very big. @308 duration? There is only 360 degrees in a cirlce.. that is a lot of overlap. I think it was a meduim riser. I will go to my my fathers house and get all the specs this weekend.

The thing is I am used to listening to newer and modular engine exhaust set ups. I need something old school sounding with new technology. I'm not talking about like 1 chamber mufflers or anything but something that will sound mean.

1320stang · Aug 16, 2005

Well, if it was an original Galaxie 427, it had a 306/306 cam from the factory with .298 lift at the lobe. There was a 330 cam with .335 at the lobe from the factory. These were all solid lifter cams. Heck, you can get a 312 Hyd. cam from Comp Cams. for a drag application, good for a auto with 3500 stall and 10:1 comp.

D.Hearne · Aug 16, 2005

EIGHTEIGHT_GT said:
The motor came in the Shelby when my father bought it but it was not the original. The original motor was a 428. This 427 came out of a 63 1/2 galaxie by the guy that my father bought the car from. He does have the original dual quad intake AND carbs for the 427. Apparently the rear one is quite rare. He also has a tri-power set up for it. He will be using a predator for it believe.The motor will sound fine. I dont know why you dont think that cam is very big. @308 duration? There is only 360 degrees in a cirlce.. that is a lot of overlap. I think it was a meduim riser. I will go to my my fathers house and get all the specs this weekend.

The thing is I am used to listening to newer and modular engine exhaust set ups. I need something old school sounding with new technology. I'm not talking about like 1 chamber mufflers or anything but something that will sound mean.

That 308 degrees spec was at .005 lift, not the more often used .050 lift now. And even though it was a somewhat long duration, the lift at the valve was only .500 . For a really impressive sound, nothing beats three dueces , with quiet mufflers, preferably romped on in a downtown street between the buildings A 63-1/2 Galaxie 427 will be a low-riser, unless it came from a factory drag car. As for exhaust, the more cubes you have pumping thru it, the louder it gets. A muffler and pipes that are somewhat quiet for a small block will be noticeably louder behind a big block.

65up2d8 · Aug 16, 2005

I have no personal experience with them, and I don't recall if I've heard any, but how about the 3-chamber Flowmasters? I would think they would be significantly quieter, and you seem to like Flows except for the decibel level of them.

Otherwise, I have heard that Dynomax Super Turbo mufflers are fairly quiet, but, once again, I'm not speaking from personal experience.

D.Hearne · Aug 17, 2005

65up2d8 said:
I have no personal experience with them, and I don't recall if I've heard any, but how about the 3-chamber Flowmasters? I would think they would be significantly quieter, and you seem to like Flows except for the decibel level of them.

Otherwise, I have heard that Dynomax Super Turbo mufflers are fairly quiet, but, once again, I'm not speaking from personal experience.

I've got Dynomax turbos on my 89 Ranger behind the 331. They've got more of a "raspy" sound. I never could stand the Flowmaster's tinny sound. I also went further with the Ranger and built an "equalizer" pipe for it, this is a 12" section of 4" tubing that the 2.25" duals feed into, then exit into the Dynomax's. This toned down them even further. Before installing this, one turbo had just started to develop a "popping" noise, the equalizer eliminated it and smoothed the pulses.

D.Hearne · Aug 17, 2005

The exhaust I had on my 427 was 428CJ manifolds, into dual 2.5" pipe and the turbos were mounted all the way to the rear of the car, a-la what the 05 Stangs have now. Situating the mufflers at the rear as such with only turn downs, greatly increases the noise level. The reason the mufflers ended up back there, was I had installed a subframe connector with a crossmember that incorporated a driveshaft loop. This took up the space the factory left for the mufflers and I had also removed the fuel tank, replacing it with a 27 gal fuel cell in the trunk, so that was the logical place to have the mufflers.

65up2d8 · Aug 17, 2005

D.Hearne said:
I've got Dynomax turbos on my 89 Ranger behind the 331. They've got more of a "raspy" sound. I never could stand the Flowmaster's tinny sound. I also went further with the Ranger and built an "equalizer" pipe for it, this is a 12" section of 4" tubing that the 2.25" duals feed into, then exit into the Dynomax's. This toned down them even further. Before installing this, one turbo had just started to develop a "popping" noise, the equalizer eliminated it and smoothed the pulses.

Interesting. I'm trying to envision exactly what you're saying, and correct me if I'm wrong (like you'd need an invitation ). So rather than a normal h or x pipe setup, which is normally roughly the same size as the pipes that feed it, are you saying that you feed the 2.25" pipes into the 4" pipe at each end and exit with duals at a different location out the backside of the 4" pipe, or are you saying that you essentially have an inlet and outlet merged into each end of the 4" pipe on each side, similar to 1/2 of an x pipe?

D.Hearne · Aug 17, 2005

I somewhat flattened the 4" pipe, then welded two 2.25" pipes into each end. I did the exit pair first, so as to smooth the flow into them. It's similar to an X pipe, but the 4" flows equal to or more than the two 2.25" if I recall my math correctly. It was a lot cheaper to build than to buy something similar that was already made up. Also, my exhaust on the Ranger has both pipes running side by side, to the passenger side of the driveshaft, so this setup was easier to adapt to it.

65up2d8 · Aug 17, 2005

D.Hearne said:
I somewhat flattened the 4" pipe, then welded two 2.25" pipes into each end. I did the exit pair first, so as to smooth the flow into them. It's similar to an X pipe, but the 4" flows equal to or more than the two 2.25" if I recall my math correctly. It was a lot cheaper to build than to buy something similar that was already made up. Also, my exhaust on the Ranger has both pipes running side by side, to the passenger side of the driveshaft, so this setup was easier to adapt to it.

I see, you are dealing with a little bit different animal. Regardless, though, I kind of like the idea for a Mustang. I agree that a single 4" exhaust chamber would be roughly equivalent to two 2.25" pipes. For full exhaust scavenging, what do you think about 2.5" dual pipes that dump into a 4" or 5" open chamber "ovalized" (is that a word? If not, it should be!!!) pipe from each end with separate rear outlets on each side of the "ovalized" 4" or 5" pipe to feed the tailpipes? Conceptually, it sounds like it would offer the same benefits as an x pipe with more balancing of the exhaust pulses and possibly more deadening of sound waves. or What do you think based on your setup?

D.Hearne · Aug 17, 2005

What you describe, sounds like what I built, just twin 2.25" pipes welded into the open ends of the flattened 4" x 12" long pipe. The open chamber is about 8" long.

Dan The Man · Aug 17, 2005

65up2d8 said:
I have no personal experience with them, and I don't recall if I've heard any, but how about the 3-chamber Flowmasters? I would think they would be significantly quieter, and you seem to like Flows except for the decibel level of them.

Otherwise, I have heard that Dynomax Super Turbo mufflers are fairly quiet, but, once again, I'm not speaking from personal experience.

It depends on how loud you want your car to be. I personally love the sound of flowmasters. With 3 in exhaust and two chambers your exhaust will be LOUD. 3 chambers have a real nice rumble and aren't too loud inside at cruising speeds. Good luck

Edbert · Aug 17, 2005

I agree with the notion that the exhaust needs to be quiet enough to hear that sucking sound from the carb(s). That sound along with the solid lifter is something that brings tears to my eyes, and it is NOT the unburned hydroflourocarbons that are making them water!

You just don't hear that kind of music anymore with the roller cams and EFI. Plus with Flowmasters being installed on every other car/truck on the road you can't hear a dang thing anyhow

Big Block 427 Exhuast set up question

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