I have a buddy with a 318 in his Valiant set up similarly to me, just with an Edelbrock 1405 600 cfm carb. The cam is a Comp XE268 (.477/.480 lift), stockish heads and compression, headers, 2.5" exhaust. He is wondering about jetting, since the plugs are a tad white. It runs ok, according to him, but that might just be relative, as I have not driven it. I am thinking that he needs to go up a size in jetting.

What do you all think? I know these carbs are lean out of the box. If he needs to go up, what number should he use?

1405, is that the manual choke version?

interesting, as I'm running a 1406 on my mag headed 318 with a 208@.050 hydraulic roller (that is as big as an XE262 at .2" lift), and I had to lean down the primaries 2 steps, and the secondaries 3 steps, and my plugs are still a little black and sooty.

Yes,it is the manual choke version. The tailpipes are black on the inside, upon inspection, but when I pulled his plugs, they were dry, ever so slightly white, but not blistered. They didnt really smell like fuel, actually had a dry lean mix smell.

My 1406 was lean out of the box & went from iirc 95's to 98's on the pri jets but it still ain't right as the choke is whacked, pulloff is non existant and full 12V makes it come off way too fast. Got to dig into it. Bone stock '83 318 ex for this carb/streetmaster intake/faster curve. Heat riser is carboned up & mileage is horrendous

there are 2 main circuits you need to think of: cruise and power. cruise is controlled by the primary jets and the top stage of the metering rods, power is controlled by the primary and secondary jets, and the bottom or lower stage of the metering rods.

the nice thing is that a typical metering rod change can be 1/2 to 2/3 of a jet size, and jet sizes on the edelbrocks are a significant change. so you either play with changing jets, or changing metering rods, or both, depending on what is needed. with metering rods, it is 5 minutes or less to change, but you need to have the right rods on hand.

the main thing to remember is that with jets, bigger is richer, and with rods bigger (larger diameter rods, for both power and cruise), is leaner.

if you are talking about richening it up on cruise, then you want to find out what rods you have and get a rod that is the same on power and smaller on cruise.

so if you have a 68/42, then you could try a 65/42, and that will richen it up on cruise and keep it the same on power.

you can get a strip kit, which has a load of different jets and rods, and if you download the manual for the carb, it has a chart for which rods/jets you need depending on how many steps leaner/richer you want to go on power/cruise.