[1badchevy]

I want to take off my Smog pump and plate off the egr along with removing the cat on my 307 olds. Any pointers or heads ups?, aside from the law and environment.

[LATECH]

Why do you want to do all that?
Is the cat plugged?
what is wrong with the A I R system.
What is up with the EGR?

[1badchevy]

It works as it should, but itm going to go with headers w/ true duals and dont want to put cats and plus i have to deal with all that jumble of a mess under the hood

[birkey]

I'm sure some people will disagree with me here, but just be aware that the egr system does keep temperatures in the combustion chamber down a little bit.

[LATECH]

The cats dont pose much , if any, restriction in the exhaust, provided they arent plugged, or the engine is running too rich, causing excess back pressure. But the single exhaust is restrictive.
Also the A I R does push air into the exhaust stream, causing some extra back pressure, mostly at WOT
The EGR does help to lower combustion chamber temps to help keep NOX low, and it helps to stop pre ignition .
All that said, with a low compression and 307 CI you wont get a real seat of the pants feel , as far as horsepower gain , from just dual exhaust, but it will sound good .
Do you still have the computer control carb and distributor? Those were designed to optimize fuel economy and werent noted for performance.
The small bore long stroke of the 307 was for the same reason.

[ap72]

EGR isnt detrimental at all, as long as its working.

If you really want to improve things you should mill the heads all you can and get a good vacuum secondary carb and tune it. Those two things will pick up power, throttle response, and mileage.

[vinniekq2]

headers are available that are smog pump friendly.The 307 is just a stroker 283,great little engine once you get rid of the factory cam and timing set. Perfect candidate for vortec heads camel bumps and a small 4bbl to go with the headers

[John long]

What year and model is your Olds?

[1badchevy]

its a 84 delta 88, im pretty sure it aint got the computor carb/ dist. And milling the heads is a good thought

[hcompton]

I did this once when i was younger back in the 80's me and my cusin took the stuff off his car. I cant tell you how bad it ran after that.

If you take it off make sure you keep the parts. You may need to go back to using it. If your carb is electric carb do not remove that stuff it will run terrible until you replace carb and intake.

You can tell if it has the electric carb. It will have a few wires running up to the top of the carb to a black thing with star style screws. If you have that leave it alone or completly replace the system. Block is the same but intake, carb and headers will be needed to make it run right again.

But take my advice with a grain of salt since I have not tried this in years. We may have just not getten all the parts replaced right. But sure enough 2 weeks later we had to reinstall the entire system bad part was we had already tosed it in the trash. we had to hunt junk yards to find the right stuff. It was ugly.

[oldbogie]

Originally Posted by 1badchevy

I want to take off my Smog pump and plate off the egr along with removing the cat on my 307 olds. Any pointers or heads ups?, aside from the law and environment.

Terminating the EGR will cause the mixture to fall lean, the carb will need a top to bottom overhaul and new jets/metering rods. The rest of this is just noise level*. If you're doing this in the hopes of finding more power you will be gravely disappointed. The problem of power in these early SMOG engines is to be found in the lack of compression and cam timing. The oft blamed smog air pump, EGR valve and catalytic converter are just hang on's that clean up the mess the engine pumps into the exhaust system. These gadgets affect on power, if no other internal changes are made, is negligible at most. Cam the engine, and run the compression up a couple points, replace the intake and hang a 650 Holley and some headers and duals on this, then the cat needs to be addressed cause it can't handle the extra flow. The EGR and AIR pump are still in the noise level.

*Noise Level being an engineering term where when testing something like an engine on a dyno making changes from run to run shows that whatever is happening it isn't enough to separate from normal variation you see from run to run with a consistent configuration.

Bogie

[John long]

Originally Posted by 1badchevy

its a 84 delta 88, im pretty sure it aint got the computor carb/ dist. And milling the heads is a good thought

I just did this to a 85 El Camino. The easiest way I know to do this is start at the computer in the RH kick panel. The harness running from the computor through the firewall will contain nothing but emissions wiring. I removed my inner fender well and traced all the components of the harness to each item. That will include carburator and distributor. You will need to replace your electronic carburator with a standard Q-jet or other carb of your choice. You will also have to replace the distributor with a standard HEI. You can block off the EGR mount, remove all emissions lines valves, relays and smog pump. Block off the exhaust ports at the manifold and your underwood will look about like a 67 Chevelle. The other posts are correct that this is not going to have a big effect on power but has certainly eliminated all the tune up issues I had with the old carburator etc.

John L

[John long]

Originally Posted by John long

I just did this to a 85 El Camino. The easiest way I know to do this is start at the computer in the RH kick panel. The harness running from the computor through the firewall will contain nothing but emissions wiring. I removed my inner fender well and traced all the components of the harness to each item. That will include carburator and distributor. You will need to replace your electronic carburator with a standard Q-jet or other carb of your choice. You will also have to replace the distributor with a standard HEI. You can block off the EGR mount, remove all emissions lines valves, relays and smog pump. Block off the exhaust ports at the manifold and your underwood will look about like a 67 Chevelle. The other posts are correct that this is not going to have a big effect on power but has certainly eliminated all the tune up issues I had with the old carburator etc.

John L

Correction to the above. I did not remove the EGR but disconnected it. I have picked up a manifold to replace the old EGR intake with but to date have not swapped them out. Getting lazy in my old age.

John L

[E.Furgal]

Originally Posted by vinniekq2

headers are available that are smog pump friendly.The 307 is just a stroker 283,great little engine once you get rid of the factory cam and timing set. Perfect candidate for vortec heads camel bumps and a small 4bbl to go with the headers

ITS AN OLDS 307 NOT THE LAME DUCK CHEVY 307


I'd leave it all on.. true duals.. why.. it's a 140hp 307
the egr, doesn't hurt anything, and doesn't function at wot
the air system is to help burn the raw hydrocarbons in the exhaust.. hurts nothing.. takes 1/2 hp to turn the smog pump..
I have a 86 SS so I feel your pain.. on the crap under the hood.. but . even if they don't test the emmissions , removal of the parts is a 2500.oo fine each.. my bet is, because they want most older cars retired.. these fines will come to light.. and fix it.. tickets will become the norm. down the line.. if nothing else. save the parts you pull..
you'll gain more from a cam change to the later 307 h/o 185hp factory roller cam. than the duals..