Dual carb question, Dellorto 40s on a 1.8L to be exact Options

[terrymason]

The problem - The car will go very lean around 2500 rpm, as if the pump jets were too small.

History:
New fuel pump (3.5 PSI to each carb)
55 idle jets
55 pump jets
140 main jets
175 air correctors
These carbs are new to the car, and I'm trying to dial them in.

The car is lean when I first start it (16 / 17 on my air / fuel gauge), but then levels out to a nice 14.7 idle when warmed up. While driving, I can give the car 20% or so of the pedal, and drive up to highway speeds nicely, but when I goose it, it will go very lean (18-22 on my gauge) followed by a series of backfires and loss of power. I started off with 35 pump jets, and have moved up to 55s, which appear to be the most popular around here. I've also adjusted the pump jet linkage, from the nut fully loosened, and moved it in as far as it would go before affecting the main throttle shaft (like 60 turns or something).

What do you guys think, do I need 75 pump jets?

[IronHillRestorations]

I remember hearing that the best stock dist to run is the 1.8 with the vacuum pot connected. Can anyone back this up?

You are getting good advice here. You have made double sure that the drop links for both sides are dead nuts the same length right? Both sides have the same angle and hit full open throttle at the same time, as well as both resting on the idle stops? There's some pretty schlockey linkages out there, and Joe's dead on with how important the linkage set up is.

I don't know Dells, but I'd try just larger idles, or just larger mains first, but probably not both at the same time.

Where are your mixture screws set at? If you have to set the mixture less than 1 1/2 turns out then I'd try larger main jets, and smaller mains if you've got to go more than 3 1/2 turns out.