Right now I have smog legal edlebrock headers, high flow cat, and a xcelerator muffler, all the piping in between is stock, even stock tips.

I’m debating having a shop build a set of duals from the headers back, dual cats, mufflers, etc.

I’m just wondering how much this would gain me in power, and is dual 3” really needed, we always ran dual 2.5” on SBCs back in the day.

what would y'all recommend for mufflers, I am concerned with ground clearance.

And would I need to get it retuned, it currently has a madz28 tune?

 

I guess it depends on your mods, i.e., do you have heads, cam, etc?

The less restrictive the exhaust, the more power, but putting mucho dinaro in the exhaust without more air, more fuel would obviously affect the end results. Doubt that going with hi-performance exhaust will require any additional tuning---but may be wrong.JMHO

 

no, it's internally stock, just the usual boltons, CAI, TB bypass, etc.

I'm sure duals would sound tons better, but that does not justify the money alone.

so I just did the math on flow area, single 3" = 7.06 sq. inches, dual 2.5" = 9.81 sq. inches, but that is just piping, I would imagine the cats and muffler to be way worse.

 

Well if you are stock on top, then your restrictions are going to be before your exhaust system and therefore become your restrictions--kinda like blowing through a pea shooter into a garden hose---doesn't make any difference how big the garden hose is, the velocity and flow are going to be dictated by the size of the pea shooter.

Just saying that while reducing the restrictions in the exhaust are crucial to gaining performance, it is the ability of the engine to intake air and fuel at a rate which results in the biggest bang and providing a system for expelling the burnt fuel in an efficient manner compatible with allowing the intake system to refill the cylinders with a fresh supply of fuel to their maximum capacity.

I see you have a CAI---that's a start. And with a free-flowing exhaust you have a good end. So now might be the time to reduce the restriction in beteen the beginning and the end.

At the minimum, I'd go with 1.6RRs and some good springs---and later on maybe some head work, headers and perhaps a cam. JMHO

 

My bad; I see you already have headers.:

 

My father in law has a built Buick 455, and he's using a dual 3" catback with an X pipe.

If it's enough flow for him, it should be more than enough for a naturally-aspirated, stock-cube LT1.

 

I think you misunderstood, I'm thinking dual 2.5" would be enough.

 

True duel 2.5 good to go.

 

You asked if dual 3" was needed. I gave an example where it is as a way to demonstrate that it is not needed here.

For most of us, single 3" is plenty.

 

none of this is really answering my original question, which is, would I see much of a power gain by going to full duals from my curent setup? any direct experience with something like this?


and how is it that BUBBA has a join date of 1969?

 

I dont think duals are worth the money, use that money to buy some 1.6RR's and a short throw shifter. That will get you faster then adding duals will. Then again it will sound awsome. Take your pick speed or sound...

 

Actually in 1969 I was a black jack/craps dealer in Reno and was driving a 58 chev with a 348, 3 speed posi (which I dropped in the parking lot of John Asquaga's Nugget one night when I had too many...) I don't know why it says 1969 because I joined the site in April of 97 when I took delivery of my 97SS and needed some advice on how to start throwing money into it...little did I know...

 

you are joking, correct?

 

No joke: I was feein' pretty good and decided to rev it up and drop the clutch and that's all she wrote

 

Check my sig and take a look at the dyno graph of the single 3" vs. 2.5"
true duals comparison. This is with stock manifolds. Note that the duals
include cats and pipe to the back (not dumps).