My son has a mildly modded 360 in a Dart, and is running a Holley 670 with headers. Compression is stock. Engine has always fouled plugs, and on startup, a deposit of black soot gets on the garage floor. Car has been sitting alot in recent months, due to body work.

My ideas:
1. Go to a hotter plug (not sure what he has in there now, but they are for a stock 318.
2. Adjust carb for a leaner mixture. (Not sure where he has mixture now.)

Also, what is the consensus on ignition timing recs?

Ideas on these 3 points?

He is in Oklahoma, I'm in Mississippi trying to help him out.

Thanks

Does it burn oil? If not it sounds like its pig rich. I'd check the ignition timing first and then start pulling fuel out by leaning the jets.

I know my 360 (with magnum heads) has the stock plugs for a 96 ram and a holley 600 that came with the engine when I bought it and man the thing is awesome. Cleanest exhaust i've ever seen on a muscle car and it runs great too.

Make sure the plugs are not very cold,autolight 3924 work fine for a near stock 360. Advance the timing and lean the mixture. Check the power valve,it must not be opening at idle.

choke/choke pulloff

Good point,often I forget the basics as I just assume anyone would check that. Worth checking.

Does it run rich just cold or is it still rich when
its warmed up

670 Street avenger? Mine was the same way. Had to back the choke way off to make it run right. Even starting it when 80+ outside it wanted to run way rich.

I agree that is sounds like a too rich choking condition. That is where to start looking. Make sure that the choke closes and opens correctly and pulls off part way when the engine starts.

thanks for the help guys, makes sense. It runs rich all the time. For the longest time it would stay on choke too long, even in warm weather. It would eventualy kick off choke. I adjusted the fast idle down a bit and it seemed better, but will have him look at choke again.

oh...and also...no oil burning. pretty fresh rebuild. He called me last night, and said dist. hold down bolt had come loose and he suspected timing problem. I had him find TDC, and he's at least in the neighborhood, but his timing light quit working....

The faster idle should really have improved the situation by the engine running faster to burn excess fuel. But the fast idle would really have nothing to do with the choke being set too rich. All the fast idle is is a cam holding the throttle linkage open a little father than at idle.

true...Moparsfor life

If the distributor hold down came loose the most that could happen is that the distributor would turn slightly changing the timing. No need to relocate TDC as long as the engine runs all that is nessessary is to hook the light on and reset the timing by turning the distributor back to the proper position.

On mixture....i had him turn the screws all the way in.

How many turns out should I start him on with the mixture?

1 1/2 out is a good start but the timing needs to be set right first.

since it seem rich all the time have you checked the float levels? The feul my be dripping over and puddling in the intake over night.

I think the float levels are ok, because this carb has the sight windows, and I have it set just below the windows, per instructions.

Update:
he got rid of the choke and it seems to be running alot better. He's going to need to at least get a manual choke going, though.

thanks for the info everyone...