Summit 3" Duster Install

-

jimmyray

Well-Known Member
Joined
Jul 17, 2007
Messages
950
Reaction score
31
I finally decised to replace the 2.5" to Walker Super Turbo muffler into 2" over axles exhaust, and wanted something to flow my 408's gasses away. Uncorking the headers at the strip was worth 3 or 4 tenths (12.7's to 12.3's), so I knew I had plenty of backpressure. Since theirs no kil like overkill, an in spite of several opnions that 2.5" through would work, I went with the 3" Summit system, with welded mufflers. These were made specifically to bolt up to the Hooker comp headers, which I have.

I took it to my local muffler shop, who has installed many performance systems in the past, and went to work. Work, says I, where in truth I was mostly in the way with plenty of silly questions and poor suggestions. Nevertheless, the system was anything but bolt in! The drivers side went in with some trouble, but did require cutting of the rear extension from the collector to the muffler. The pasenger side, though, was another story altogether. The over axle pipe seemed to be bent incorrectly, and did not want to fit. He had to cut the rear collector to muffler extension on both ends, slightly dent the front collector to muffler extension to clear the tranny crossmember. He also had to cut the over axle piece on both ends, and swell one end to allow some play. Finally, the tailpipe extension required 3 additional bends on his non-mandrel machine to fit properly. It too 3.75 hours! But...he only charged me $100, and I was expecting pay more, but business was slow. All said, if I would have tried this at home, I would have failed miserably!

He was kind enough to cut the A-body tips off of my old 2" pipe, and fit them to the 3" pipe. Oddly enough, the tips flared from 2" to meet the pipe into a 3" diameter, which was then shaped to form the rectangle tip we all know and love. Therefore, he was able to cut the tip at the end of the flare, and he slightly enlarged the 3" exhaust pipe for the tip to fit into. After welding, it almost looks like it was supposed to be that way. And, I did not have to buy a $130 set of new tips!

Finally, from the rear of the car, the sound is louder than what I had at idle, and is louder when you rev the engine. But, it is quieter inside the cabin at driving speed. Not sure of the physics behind that one. I am happy with the final result, and seat of the pants seems to indicate that it revs more freely. I hope to test it this weekend with my new 3/8" fuel line. Maybe, just maybe, I can get closer to the 11's, with the exhaust hooked up. That unhooking headers at the strip is a pain!

33.jpg


31.jpg


30.jpg


35.jpg


37.jpg


39.jpg


40.jpg
 
Seeing as you put a new system on you should have installed dumps after the collectors,much easier to open at the track then the headers,and nothing will be lose or dangling...
 
nice I have the 3in X pipe after my headers right into 40 series and then thats all. o ya running a 8 1/4 with SS springs how do your tires not the springs? mine barley clears with 4.5 backspacing and a 1/8 spacer
 
looks good to me, dont think those small non mandrelbent bends that far back in the system makes a big diference anyway since the exhaustgas has cooled of some that far back anyway, about it not being perfect out of the box thats kind of normal, i have installed quite alot of systems and i have yet to find a brand that has always installed perfectly out of the box... those mufflers looks like flowtech afterburners, i like the sound they have!
 
why? jw
But it is good to know you have something stronger, I will be going to a 8 3/4 soon also from a B Body and just will move the perches in so I can Use Bigger wheels and bigger tires
 

1. I picked up a B-body rear with the intention of narrowing it, since I had already bought wheels, and their offset would not work with the wider B-Body. So I could not do as you are going to do.
2. By the time I costed everything out, it was going to add another $500 to the build (new axles & bearings, seals, cut & weld, etc.) I could sell what I had, get my money back, add about $300 and have a Dana. (Did not do a good job thinking that through.)#-o
3. I had a Dana in my Duster when I was 19, and I wanted another one.
4. Coolness Factor, having the chrome cover peaking out from behind the gas tank!

However, if I had not already purchased wheels, I would have just moved the perches and bolted in the B-Body! But I don't regret the Dana, not 1 little bit.:-D
 
Ah see ya my wheels will stick out some on the street with the B body rear, but at the track they will tuck righ up under
 
Looks good there Jimmy Ray. Like my 2-1/2 incher from Jegs, oly bigger.
 
I think that the exhaust system was the one to thank for the gains you saw. Getting more fuel to the carb is important, but the carb can still only put so much into the motor at a time. So unless you can get below what you got with uncorked headers and 5/16 fuel line I think that just the exhuast upgrade helped
 
It's the fuel line more than exhaust IMHO!

Nice job on the pick up. Not uncommon for cars with marginal fuel line size upgraded to a size that will provide enough for the car.

5/16's fuel lines SUCK... :-D
 
I think that the exhaust system was the one to thank for the gains you saw. Getting more fuel to the carb is important, but the carb can still only put so much into the motor at a time. So unless you can get below what you got with uncorked headers and 5/16 fuel line I think that just the exhuast upgrade helped

That, and jetting, and Bleach Box got me about .15 under my previous best with open headers. The 3/8" fuel line did not hurt, but not sure if it actually helped.
 
It's the fuel line more than exhaust IMHO!

Nice job on the pick up. Not uncommon for cars with marginal fuel line size upgraded to a size that will provide enough for the car.

5/16's fuel lines SUCK... :-D

Is it common for cars to run the same with headers vs. a free flow exhaust? Below are my previous bests, with open headers, and the new best, with 3", 3/8", jets, and better Bleach Box slick warmup.

Notice how the ET is progressively better in all 4 measures. That is probably the Fuel System/jetting exclusively. Unfortunately, the red 1/4 time is estimated. All of my best 1/8 mile runs up to this point were on bracket nights, when they were not even timing the 1/4, so it is estimated at a 1.577 multiplier of the 1/8 mile time, which is the ratio of my 12.26 run.

08.jpg
 
want a real test to see what it was? take the exhaust off and run open headers with just the fuel line and that will show you how much it helped....
 
want a real test to see what it was? take the exhaust off and run open headers with just the fuel line and that will show you how much it helped....

Yea, I thought the same thing. May have to try that next time out.
 
Weather probably picked you up some as well.

Since the 60' didn't change much, the exhaust/open isn't creating much difference down low. Next time, run it corked up, then open to see if it makes a difference.

I've had and worked on cars that made .15-.25 pick ups changing the fuel line diameter.

The two items that picked it up were the line change and jetting jump. I'd love to see what the car would have run with the 5/16 line and bigger jets? I bet it wouldn't have gone 109+. Your test with the bucket proves the point!
 
we will see when he goes out next week? or ASAP if he goes faster than he did before with the headers only, I will change my whole fuel line system
 
-
Back
Top