Here is the digest version of my posts about it:
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I finished up my L69 rebuild today and did the exhaust. I did true duals. I opted for side exits right before the rear wheels because going through the rear suspension would have been a BIOTCH.

And holy ****... it sounds so ****ing badass. It totally blows away the dual exhaust mustangs have... woohoo!

Very deep, mellow tone... and it's emissions legal!

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I spent $50 in bends and welded it up myself. I also took off the stupid AIR tubes off my headers and welded the holes up in those.
Ground clearance is maybe 1" difference from stock.

No tubes were needed to "equalize", that is a total myth (IMHO). I cut the stock y pipe so it was two seperate pipes (basically had about 6 inches from the collectors of the headers left on each side. Then I bent pipe to the stock cat converter location, running them side by side. I used Catco cats, they are very small and fit wonderfully. Then I had to do a bend in a pipe, and then use a reciprocating saw to cut out just a small portion of the bend to hook the Dynomax "bullet" style mufflers after the cats. After that is up it's easy from there, I bent and cut two pieces of pipe from the mufflers, passenger side dumps out at the rear passenger wheel, driver side dumps out at the rear driver wheel. Welded on a "mild" tip on each side... nothing fancy just stock-looking chrome dealies. It really looks awesome, you can't really tell it is side exit without being right there.

Like I said, the sound is GREAT! I'm running a little rich because I had to guess at my carb settings with the new cam and I haven't gotten it dialed in yet... and I have NO evil Whorla style popping! That ****ing rocks... with my STOCK exhaust it popped like a mother****er when you let off and now it's just smooth and deep. I have heard a lot of exhaust and NOTHING has sounded this good... maybe it's because I did it myself, I dunno

Also, backpressure is a REALITY! You MUST have it! I had my car open headers for a day and it would NOT idle ! Put my Matt Performance Parts (hehe) exhaust on and it idles all day at ~ 700-800 rpms.

Now I need to put in my custom digital dash I fabbed up and my leather 4th gen seats I have and I'll take more pics... this car is really looking great!

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btw, side exit is nifty... you know that sound you get going through a tunnel or under a bridge? well the side exits fire right at the walls.... makes a GREAT effect....

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I did all this for $250 cash outlay. Not bad. You don't have to spend a fortune for great exhaust.

 

good job dude. sounds like your pretty handy with fabing up your own stuff. now hurry up and finish the rest of the work so we can see some pics

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• 83 Z28--ttops, 200k miles--very ragged out. sold, thank goodness
• 74 Z28--slightly modded 383, TH400 tranny, not too quick but fun to drive

 

Yea, I want pics dammit!

 

Matt, it was like you read my mind or vice versa. I have a flowmaster crossflow and it isn't loud enough for me.

I checked with the DPS in my area, and I can't have exhaust that exits in front of the rear tires, as yours does. This is because of the possibility of exhaust gases leaking inside. I've seen some of the late-model Mustang's with stock side-exiting exhaust. I guess it's o.k. if it comes from the factory like that. You mentioned that you can't really tell that it dumps to the sides. Maybe, it's something that officers don't really check in my area? Also, the DPS said that if an officer thinks that an exhaust is too loud, that spells ticket. Have you heard of anybody getting pulled over for having bullets on their car?

If I did this upgrade, I'd probably have both mufflers exit on the passenger side. If I had the driver's side exit on the driver's side, I think that the fuel filter would be a pain to change(this is a fuel injected car). I'd probably have to insulate the fuel line too.

The only other option is to just replace the flowmaster with a single bullet exiting the rear. Or finding some way to have two exit the rear. I think a muffler shop that I've gone to can do that(hopefully).

Congrats on a job well done. What size did you use? 2-1/2", 3"? How's the interior sound?

 

I was planning on doing basically the same thing. i am gonna get the $80 summit headers, 2 collector flanges, (2) 2.5" pipes about 3' long and dual flows and nothin else, so it dumps in front of the axle. I like this look on old chevelles and stuff where you can see the ends of the mufflers from behind the car. And I believe it will sound freakin killer!

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1983 Firebird
TH700R4 Auto
Small Block 400
LG4 ECM, Intake, Carb, Distributor, etc.
Soon to be non-computer.
Clarion Head Unit 45X4
2 Pioneer 400W 12" Subs
Third Gen Performance
"A four cylinder is half an engine."

 

Do you have cats on the car? How did you hang the mufflers? Did you message the floor pans, or just used universal hangers and prayed? Where did you get the bends? I assume they are mandrel bent.