just back from the dyno. running lean

As another data point, my '77 likes .60s.

Birdman

 

The a/c will be dependant a bit on your exhaust and some other things, as you see the a/c effect mostly in the higher rpm ranges. A 200 will probably be ok for many applications, but you describe going lean at high rpms --- so the thing to do is richen up, then slowly tweak back the mixture strength using a dyno or mobile A/F monitor such as an LM-1. As far as rwhp, depends on a lot of things including cams and exhaust, ignition working well, airbox configuration etc.

The idea is to deliver a mixture richness from mid 12's to mid 13s, perhap low 14s to the cylinder. If your carbs are doing that across the range, the rest is up to the engine... Ferraris begin to miss at an AF of about 15 under load in my experience

I am a bit biased in how I balance my mains and idles to smooth transition. As you know, Ferraris tolerate and even like fairly rich mixtures (at the expense of plugs if not hot enough). To use my well honored friend Birdman, he states his car "likes" 60s. While I cannot speak for him, this might be translated as feeling a bit smoother in transition which seems a bit more powerful. What the 60s are doing is pushing transition mixture coverage of the idle circuit higher in the rpm band. Conversely, I like to go with the smallest idles possible (as most of your day to day cruising is actually done on the idle circuit) to have better economy, power and less fouling with a mixture strength closer to 12 - 13 and bring down transition coverage from above using a larger main jet. The risk is that if you do not cover mixture requirements in the 3 - 3800 rpm band with either idle or mains, you will feel a flat spot on throttle opening before the accell jets kick in.

Remember, some US spec Ferraris actually spec'd 125 main jets for leanness in emissions with similar lean idles. Reaching down with 140/143/145 mains and 53-55 idles gives you a better transition, more power and less fouling susceptabilities.

What I gave you below was a recommendation of where to start with your tuning, as it will be a hair rich probably, but safe. If I had to guess at the final numbers, they might look like:
140 mains
ET/ F24
200 A/C

You may have an E - tube of F-36, in which case you may end up jetting a hair richer, or not.

Start rich, then tweak back leaner.

Have fun and good luck!!!
rt