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Topic Review (Newest First)
12-06-2003 11:16 PM
troy-curt In the last 50 years I've built many...many cars and hotrods. I have never yet putt twin pipes on one that it didn't help. With mufflers and 2.........3 inch pipe there will be enough back pressure.

Even with the headers uncorked.LOL


69 ss rs full custom camaro 98 ISCA grandchampion
69 ss rs bb camaro wifes driver
66 Elcamino 350/all dz parts,ac,windows,loaded,my driver
69 ss chevelle bb conv.fresh frame off
26 T sedan street rod
12-06-2003 07:07 PM
badknuckles keith b is right some cars dont need duals and on a small 305 its just a choice of taste and looks
12-06-2003 06:56 PM
KeithB123 Ya see...the last 2 post would agree with a dual but having small exhaust pipes. So it depends on the "Complete" system.

In some cases , like street cars..true duals are over rated.

Good luck...let us know what you decide and the outcome!
12-06-2003 06:50 PM
badknuckles i would run 4 inch pipes right to two 1 inch briggs and straton mufflers runs great on my lawnmower.
thats a joke im trying to lighten things up.
i would go with dual 2and1/4 inch pipes and dynomax mufflers with a 305
12-06-2003 02:31 PM
lolathemustang I have a 289 with dual exhaust and I think it helps. It is small 2" tubing that goes all the way out the back so as to build low-end torque, but I like it. It's probably not better than a larger single exhaust but I like the look of duals. I have full length headers (cheaper than shortys) and I think they helped a lot over the entire power range. Just my opinion.
12-05-2003 03:00 PM
stoney 81ta tks for your reply and advice keith and all others btw i like the leafs so i guess it stays maybe?
12-04-2003 06:11 PM
KeithB123 Ah!!

Well. I`m originally from Buffalo.......soo ...if you like the Leafs keep the converter on. If you like the Sabres take the converter off.

12-04-2003 06:00 PM
stoney 81ta so what u suggest keith is to use headers and single exhaust what about a cat the car has one on now as far i know i have to use one in ontario if the car came with it. thanks all for your inputs.
12-04-2003 05:34 PM
gt2betubbed That makes a lot of sense Keith! Thanks for tha breakdown.
12-04-2003 04:19 PM
KeithB123 Yes Poncho thats what I was trying to say. With a a smaller displacement 305 or even a mild to mid 350 you do not want too much free flowing exhaust because all your performance gains will be too high and your bottom end will fall on it`s face. Now if you put together a 350 that has a huge cam and a high end intake then I could see a more free flowing exhaust. But with a 305....I would go with 1 5/8 "Shortie" headers and put on a Y-pipe. The 305 has it`s power on the low end...Why take away the power range? The 305`s power range is with the lower rpm`s ...if you take that away that 305 would be a dog.

Now if you don`t believe what I`m saying...try this.......( here`s a in-expensive test for you ) Put your headers on and then put on a couple of cheap flex pipes with the mufflers you were going to put on....just wire it up and Drive the car and you will see it won`t have any acceleration.

I have experimented with the 305 and 350 with a few different combos. I haven`t found a dual set up worth while for a "Street" set up. BUT...if you toss on your headers with some small tubes to give it some back pressure to help out the low end.

Like Luci touched on ...there are charts out there that tell you where your performance is. December issue of Car Craft touches on headers and it gives a chart, the bigger headers gives more higher end performance. It`s the same thing as your exhaust pipes.

I`m sure that 305 is not running at 4500 + rpm`s on a regular basis.

Good Luck
12-02-2003 09:11 PM
poncho62 The smaller header size will give you better bottom end torque. You will lose some on higher RPMs.
12-02-2003 09:05 PM
KeithB123 Some exhausts flow better than others.

It has also been said that " Smaller" Exhaust Header Tubes perform better on a Small Block Chevy. Example- 1 5/8. I agree with experience.
12-02-2003 06:55 PM
lluciano77 Man I don't usually respond in run on sentences but here it goes single exhaust can flow as much or more than dual exhaust if you increase the pipe diameter to compensate I don't have the chart readily available but I have one that converts dual to single requirements and back.
12-02-2003 06:42 PM
digitalfrek i dont think it will cut power because i reduces back pressure but i dont know it might
12-02-2003 06:40 PM
stoney 81ta if true dual will cut performance why? iam not a expert but i was thinkin headers with dual would be much better than stock set up with headers.also is heddman headers good quality.As u all can tell with my questions my experience with all this is new thanks for your inputs. Its nice to find a site that is really friendly and helpfull to others willing to learn.BY stockset up i mean factory
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