Stock 305, thoughts on 3” tubing?

[olds307 and 403]

You have a better system than the factory G body "high performance" exhaust systems, good enough for a 305. 4 and 6 cyl cars can definitely be fast but they should be kept quiet. Every 4 cyl sounds bad, period. Some 6 cyl sound Ok. Guys come on the Challenger site and claim their 3.6 sounds good, it doesn't due to the manifold in head design. The factory resonators filter out the bad sound. Yeah, your 305 will sound mean, just don't go around thinking you are the king of the stop lights.

 

[Clone TIE Pilot]

I would use a 2 1/4 true dual exhaust with a "x" pipe and or cross over pipe .With a decent set of mufflers . High flow cats are an option depending on the state,

Dual exhaust, even with dual cats is still illegal for G bodies in all 50 states. Only single cat exhausts are legal for G bodies. Its just some states don't bother enforcing the laws on older cars for the time being.

 

[Michael Watts]

So .I have a similar system in my 1981 El Camino SS with a 290 HP 350.And I passed the emissions test the last time the state ran one .So its up to the individual if they want to .Since they arent running them anymore.

 

[abbey castro]

Dual exhaust, even with dual cats is still illegal for G bodies in all 50 states. Only single cat exhausts are legal for G bodies. Its just some states don't bother enforcing the laws on older cars for the time being.

Its not illegal in Bell County TX. It is not an inspection item. I'm running long Hookers with after market Cats, X Pipe with Flow Masters on 2 1/2 in pipes. Inspection items are all lights, horn, brakes, e-brake, wipers

 

[08Malibu]

Dual exhaust, even with dual cats is still illegal for G bodies in all 50 states. Only single cat exhausts are legal for G bodies. Its just some states don't bother enforcing the laws on older cars for the time being.

I run true duals, with an x pipe in NJ. My car has been except for like 15 years already.

 

[Clone TIE Pilot]

Its not illegal in Bell County TX. It is not an inspection item. I'm running long Hookers with after market Cats, X Pipe with Flow Masters on 2 1/2 in pipes. Inspection items are all lights, horn, brakes, e-brake, wipers

Its illegal under Federal law for all 50 states for steet cars and trucks. Part of the Clean Air Act of 1990 signed by Bush senior. Its not legal to install dual exhaust into any car that didn't have dual exhaust available as a factory option.

Furthermore, no G body was certified to have dual cats as part of its low emission package, only single cats.

I run true duals, with an x pipe in NJ. My car has been except for like 15 years already.
I

I live in NJ too, you and I are only exempt from state ran inspections and testing. However, we are not exempt from obeying federal emission laws.

In short, your car is emission illegal and therefore road illegal. Just NJ doesn't bother to enforce the law on older cars for the time being. Granted cops can still give you spot inspections and tickets for non complance.

Its similar to the legal situation with marijuana. A state like CO may legalize it but its still illegal under federal law.

 

[08Malibu]

Its illegal under Federal law for all 50 states for steet cars and trucks. Part of the Clean Air Act of 1990 signed by Bush senior. Its not legal to install dual exhaust into any car that didn't have dual exhaust available as a factory option.

Furthermore, no G body was certified to have dual cats as part of its low emission package, only single cats.


I live in NJ too, you and I are only exempt from state ran inspections and testing. However, we are not exempt from obeying federal emission laws.

In short, your car is emission illegal and therefore road illegal. Just NJ doesn't bother to enforce the law on older cars for the time being. Granted cops can still give you spot inspections and tickets for non complance.

Its similar to the legal situation with marijuana. A state like CO may legalize it but its still illegal under federal law.

I have qq plates, I’m good. There’s worse offenders to mess with. I don’t run a front plate either. I’m a real bad *ss.

 

[Jim Rockford]

I just installed a set of hookers and a nice 2 1/2 dual exhaust with a hooker X pipe and I can tell you even 2 1/2 is a tad too much for a 305, doesnt hurt its just I can feel the restriction now is the small bore of the 305.

 

[abbey castro]

I just installed a set of hookers and a nice 2 1/2 dual exhaust with a hooker X pipe and I can tell you even 2 1/2 is a tad too much for a 305, doesn't hurt its just I can feel the restriction now is the small bore of the 305.

OEM design systems are based on a bunch of parameters. A 305 from the factory has the right diameter pipe. Anything above drains it. My son is a sw engineer for a European simulation sw company and they run programs that are used by almost all OEMs on exhaust as well as intake efficiencies. I've seen a simulation on the effect of exhaust diameter is interesting. Everyone knows that the diameter and length of the tubes as well as the collector influence power.

 

[Clone TIE Pilot]

OEM design systems are based on a bunch of parameters. A 305 from the factory has the right diameter pipe. Anything above drains it. My son is a sw engineer for a European simulation sw company and they run programs that are used by almost all OEMs on exhaust as well as intake efficiencies. I've seen a simulation on the effect of exhaust diameter is interesting. Everyone knows that the diameter and length of the tubes as well as the collector influence power.

Displacement affects what the optimun cross sectional area is for both the intake and exhaust of an engine. Also depends on what RPM you want peak torque to occur.