Background Info: 350, 9:1, performer rpm intake, headers, 2400 stall converter, 700r4, 3.73, Holley 4160 600.

The car runs great. No hesitations, no flat spots. But at idle the thing will burn your eyes and it smokes pretty heavily.

On a cold start, the motor doesnt smoke, but you can still smell it being rich. When the engine warms up it smokes.

The choke has been converted to manual and the fast idle cam is not contacting, so that shouldnt be the problem.

I have double checked everything that I can think of. The floats are set right, I currently have 63 main jets, the transition slots are set correctly, idle screws have been adjusted to greatest vac (roughly 1.5 turns out), power valve is good and a 8.5 (could probably go higher), idle vac is 16" in neutral, 14" in gear, idle speed is right around 900 in neutral and 850 in gear.

Timing is set at 34 total. 24 static, 10 mechanical

I dont know what else to do to get the smoke to stop. It doesnt smell like oil, it smells like raw gas.

What all determines the fuel mixture at idle? What else can I try? It is embarassing to drive the car when everybody behind you at a stop light cant breathe.

 

Check fuel pressure could be a little to high.

 

It is sitting at 5 psi.

 

not too many carb guys on here I reckon.

I'll stick with s10v8 and thirdgen.org for this then. I'll post up whenever I do figure out what is causing it.

 

Do you have vacuum advance on your distributor?

 

yes. It is set to bring in 14 more degrees max. Connected to metered vac.

 

Do you mean ported vacuum? You might try manifold vacuum to see if it helps on idle since ported vacuum wouldn't have any effect when the throttle blades are closed. You should be able to see it move if you connect/disconnect it or verify it with a timing light. The other thing is make sure your power valve isn't blown out.

 

power valve is good.

vac is hooked to the metering plate port, whichever it is called. I think I have heard it called both before. Regardless at idle timing doesnt seem to affect the smoke or smell.

I actually installed a few new plugs and let the car idle. Checked the plugs and they look practically brand new. No sign of it being rich.

I then tried restricting the IFR with a small piece of wire. No affect. Im just going to drive it and see what happens. Thanks for the help though. I have just tried everything I can think of besides swapping carbs around. At the moment that isnt really an option. When I get another one available, I will try that though.

 

What about the floats, are you sure its not overflowing.

 

yep. I have double checked everything.

Im beginning to wonder if synthetic oil smells like fuel when it burns.

 

After doing everything I can think of, I have finally decided that it must be oil burning. Synthetic oil must smell like fuel when it burns. That is the only explanation I can come up with.

I restricted my IFR and with main jets at 63, my plugs are white, I have a slight lean stumble, and the car still smokes at idle. Im guessing valve guides are getting some wear since under decel the car doesnt appear to smoke.

No I just need to unrestrict my IFR or bump my mains back up to 65 and be done with it.

 

Just as a further update, I have decided that it is an oil based smoke.

I changed the oil from pennzoil synthetic to castrol syn blend and the smell of the smoke changed completely. It no longer has as much of a "gas" smell to it.

Also I leaned out the idle mixture screws to the point where the motor would barely idle and it still smoked the same.

Im saying oil. Not sure if it is rings, seals, or guides. At this point it doesnt matter. Im going to have to drive it as is for awhile.