Hot Rod Forum banner

how much extra power

3K views 17 replies 9 participants last post by  troy-curt 
#1 ·
reastoring a 81 ta 305 chev motor too bad like to keep it stock for now limited budget just want to add headers and true dual exhaust approx how extra horsepower will come from this if ant all replies thank you in advance. btw im monk 81ta from b4 puter crashed had to reregister new name.
 
#4 ·
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
 
#6 ·
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.:sweat:
 
#9 ·
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
 
#14 ·
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.
-Ben
 
#18 ·
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

Troy


__________________
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
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top