600 CFM vs 750 CFM...

yellow rose - I'm finding that very thing, at idle anyway. I've heard idle AFR's from 13.0 to 14.7. Ideally I would like it to idle at 14.7. But getting near that it gets VERY rough, sounds like it could stall at any second. I set it at 13.0~13.5.

Interestingly, my WB has been mounted on my left collector, and was where the readings came from. I think it was wise on my part to ask my exhaust guy for a bung on both collectors. Yesterday I got to thinking, "what if my left bank is at 13.0~13.5, and my right bank is at either 12 or 14.5?" During idle tuning, when I would turn 1 idle screw I would turn the other approximately the same, but that doesn't guarantee evenness.

So last night I switched the sensor over to the right bung. Lo and behold the right side is idling at the exact AFR's ... 13.0~13.5. I was surprised I had kept them so even.

I've heard that little spikes (at idle) to 13.5 or higher is a misfire, and the WB reads that as lean. Well, now that the AFR is painting the picture, it has frequent misfires at idle. I can see it and feel it. I thought a misfire would be a rare occurrence. But it is not. At least not for this engine.

I decided to go with a 1405. It's already set up for a manual choke, and I can feel exactly what the choke is doing through the cable ... and it was $31 less expensive anyway, and no additional wiring. I've just put the order in for the 1405. I'm hoping the higher air velocity will also lead to less misfires due to better atomization even at idle. We shall see.

In the other thread, I mentioned that I would like this car to be as close to an every day driver car as is possible. I won't daily drive it. But I want to be able to turn the key, have it fire up. And have good road manners. I don't want to be ready to put it on craigslist due to it being a PITA to deal with. This tuning stuff is FUN. But like I said, I'm as far as I can go with the 1407.

As for the question about "how much." I will sell the 1407 for $200. I think it's a $348 new carb, from what I remember. So I think that's a good deal for a like new carb. Includes the original mains and rods, intake gasket and carb gasket. Ships in the original box.


7milesout