To emit or not to emit

[Billschroeder5842]

My 75 road runner is being kept pretty stock. It is a 400 bbl.

I recently started to put together all the emissions equipment. I know it might effect performance a bit but I don't mind; I don't race the car around and am looking more toward smooth and dependability.

That being said, has anyone kept their car emissions intact but are able to tweak a bit of performance? I put on an NOS OSAC this weekend along with hooking up the dual snorkel heater system (yes! I even set up the exhaust heat shield). I did not notice any performance degradation.

Anyone try anything?

 

[A383Wing]

I have always kept my emissions intact & working on all my cars...the snorkel heater system is only functional when engine is cold....

a good dual exhaust won't be a bad thing....other than that, don't try to modify it too much....the engineer guys were actually pretty smart when they designed this system back then....

 

[Billschroeder5842]

Yeah, I agree, I'm old enough now to want no hassles. Plus, this is a cruiser; rock, rock solid at 90. My 69 charger was a 0-75 lightening fast but not much more. This RR is a beast on the highway.

 

[HT413]

Emit. Emit with pride.

 

[Coyoteduster]

"Emissions? We don't need no stinking emissions!" :laughing4:

 

[Darter6]

Only thing I would do is can the cat(s). After 39 years they tend to not flow very well. My doba runs fine until the thermoquad opens then sounds all plugged up and runs out of steam at 3800 rpm. New duals will be soon.

 

[MarPar]

emit?? oh, I emit all right. :methane:

 

[Badvert65]

1975 wouldn't have had much emissions stuff. Cats weren't mandatory until 1976 and later. EGR, fuel vapor controls, retarded timing, that should be about it. Lots of friggin vacuum lines.

 

[roadrunnerron]

On cars of this age you are not likely to be e-tested. The more likely scenario is that the cops will check under the hood to see if the right stuff is present.

On my own 75 I had the engine rebuilt, blueprinted and balanced. Compression ratio was increased to 9.3 to 1 so that it still runs on regular gasoline. other modifications were 30 thou over KB pistons, a warmer cam, dual exhaust with no catalytic convertors and a 600 cfm Edelbrock carb (in lieu of the 850 or was it 950 thermoquad). All other vacuum controlled emission equipment is in place. Don't care if it works or not as long as it is in place for a visual inspection.

Estimated HP is 325.

 

[Darter6]

Badvert65, Yeah some did, some didn't. My 75 Charger 360 had a cat. My 76 318 Aspen did not.Just a air pump. Both bought new. Ma Mopar,Go figure..

 

[Billschroeder5842]

Did all 75 400 come with an EGR valve? Mine does not have one and I honestly can't see how one would fit under the carb linkage? I have a hose calls for it.

 

[A383Wing]

is there a diagram that shows it on the under hood vacuum diagram sticker?

 

[Cranky]

Cops check under the hood in Texas? Never happened to me and the emissions controls on a 75 probably made it put out more than a car without all that junk and was tuned well instead. Retarded timing and lower compression was supposed to lower NOX but it raise other emissions. Those cars got sorry fuel mileage too because of the detuned nature of them. How does a car that's detuned have less emissions than one that's tuned well? Hell, my 66 Belvedere pust out less NOX than my 95 Dakota does!

 

[Crazy Dave]

There are 3" diameter cats, used in large trucks, I used them for my cat/muffler for my 79 to be street legal. They are expensive but flow like gang busters.

 

[Cranky]

There are 3" diameter cats, used in large trucks, I used them for my cat/muffler for my 79 to be street legal. They are expensive but flow like gang busters.

You do know that this thread is nearly 3 years old, right?