OK, 1972 FJ40. original motor, just rebuilt, mild cam, stock carb and a header. I can not get this thing to idle to save my life. The thing ran fine before the rebuild and I spoke with the cam manufacturer and he said it was just a bit more lift than stock so there should be no running issues. It acts like an intake leak, but there is none. I plugged off every possible vacuum line to distributer, booster, ect. and it still will not meter fuel right. I bought a new rebuilt carb thinking it was the carb but same... Does anyone have any ideas? I am at a total loss and have been at it for a while...

I would guess you need to re jet it (Larger) now that you've added the cam and header.

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Does it fire up at all? If not it might be a cam not dialed in correctly, or maybe distributor out of phase. With just a mild cam and headers, the stock carb will still a least run. I'm not familiar with old FJ's, but basic american V8 tech still applies. Keep us posted.

Yes it does run. but I have to have the fuel screw all the way in. I can see the timing marks in the window so the distributer is stabbed right. Right?

I don't know what you mean by window, but if the timing mark is in the normal location, that should be correct. But the cam can still be out of phase. rereading your first post, a second carb is still doing the same thing. The odds of it being a carb issue with two having the same problem is slim. You said it does run, I bet the cam is off a tooth. I believe a vaccum gauge will show a very weak signal. Typically whan any inprovments in breathing are made, headers, intake etc. the carb needs to be richened a increment or two. But it still will run fine, the plugs will show a lean condition. With all the old carbs I've ever worked on, turning the mixture screws in leans it out, which is the opposite of what you have. It is very easy to misalign dots on the timing gears, you may want to recheck that. It's a cheap fix, but can be a little time consuming. If anybody has any other thoughts, I'd love to read them. It's been several years since my troubling shooting days. I hope this helps, good luck!