600 CFM, all I need. Check my math!

Spent ALL DAY yesterday (Saturday) working on my truck's brakes. Not done either, now I'm going to replace the calipers, the driver's side is stuck.

But today, I got the wideband installed. It went really well. Didn't take too long. You gotta see how I mounted it. I don't love the mounting, but it was simple, easy and it works. I'll get a pic of it to show you guys. The thing is a b---h to start when cold. Before I cranked it, I checked the carb to see what was hooked up to it based on watching Edelbrock videos.

Turns out the vacuum was attached to the driver's side port. Which as I recall is called total vacuum. Which I don't think it correct for this car. But the kicker is, the timed advance port was WIDE OPEN. So ... I switched the vacuum hose to the timed port, and plugged the other side. I would image the choke was being defeated by having this port open. So, after some frustration, I got it cranked and here is what I saw. A little surprising.

With the advance hose switch and the other side plugged, the idle was too low. I noticed this later on in the test drive when it was fully warmed. And went through the lean best idle when I got home.

Cruise Mode - Rich. Not WAAAY WAAAY rich. But rich.
Power Mode - Not too far off, but seemed a little on the lean side.
WOT Mode - Just a hair lean.

Based on this, I think the first thing I'm going to do go with 1 step lighter spring, a 4" (of Hg) spring instead of the stock 5" spring. This will help the vacuum overcome the spring more easily and keep the metering rod further down in the main jet. The effect would be leaning it up, in cruise mode.

Also, just before I got home, I saw that at a near stop, and hitting it, it would bounce into lean (and either stumble or almost stumble) and then go real good. So ... on Friday (pre-wideband) I moved the accelerator pump to the smallest shot. I'm going to wind this post up and move it to the middle shot setting and run it again. I have to do this from a slow roll or it just smokes the right rear tire.

Loving the wideband feedback! And it appears as if all the guidance above is correct. The carb is not too big, it can simply be tuned. However, I wonder if a 600 CFM carb with electric choke (& electric fuel pump) would start better.

I'm probably going to just go ahead and buy the carb tuning kit from Edelbrock on Monday.


7milesout