My "L29" build.

[jonbills]

Yeah my L24 certainly did, although the pmac/mjp airbox goes a long way to fixing it.

I think my plan of attack on the midrange is to go a size leaner on the emulsion tubes and +10 on main jets.

 

[jonbills]

I'm still beavering away at this - yesterday I re-opened a 4th hole in the progression hole well to lean it out a little more just off idle and keep it going until the main jets start which seems to have worked reasonably well, although still a little rich (AFR 11.5 - 12) at 50mph.

for the record, the hole sizes are now 1.2, 1.0, 1.2, 0.5. I'll probably take that last hole out a little next weekend.

I did try the 'next leanest' emulsion tube as advised by Des Hammil's book - a 7772.14. It didn't work out well - main circuit started much later and then was very rich

so I've been researching customising emulsion tubes -
https://www.youtube.com/watch?v=1pkFSA_rRFI explains how the E tubes work and that you can add holes to correspond to engine speed (well, vacuum really) to make it leaner there.

It all makes sense, although there's no easy way to know where to add the holes.
My current E tubes are 7772.5 and there's a ring of holes just about or just below the fuel level in the carbs - this is what makes them start as early as possible.
I've added a couple of experimental holes to them about 5 mm lower in the hope they'd make it leaner 2.5k to 4k, but they don't, they lean it out briefly at about 6k.

so next step will be a couple of experimental holes 2mm below (above in the photo) the starter holes.