Mik 42 will be fine

+1 on the 42 HSR

Is the SU giving you problems? I know they need tuning more than most, but a well set up SU works. what size is the SU you have?

 

Look at the SE CV Carbs. I've got a 44mm & love it.

Get the S&S G carby mate have it tuned and they work bloody beaut. Fit the bigger  element and you can't do better.

i got rid of the stock cv carb on mine and replaced it with an S&S E carb and had it set up on the dyno. much better.

First off, there is no best carb for a Harley, as long as they are tuned right, a CV40 flows about same air as the S&S E or the Mikuni HSR42 just some people don't know how to tune them. i think a cv44 would suit you it should flow enough air, they work great as they ajust to ellivation and being constant velocity you don't have to worry so much how hard you open throtle they excellerate.

but then we come to the biggest problem, if it's an evo softail & you ride it flat out it will eventually fall apart from the vibration, you have to keep checking things are not loose or cracked. but i've managed to ride Harley for a long time and a long way and at reasonably fast speeds. just have to understand them. if you want to ride fast & not touch the bike, might be the wrong bike. but give it a go see how you go.

 

Krash you have touched on something that probably needs more discussion perhaps a new thread? Elevation.
Some factors that play into tuning a carb
Elevation (Pressure change)
Temp
Humidity
Dew point

I have used SU's on Flatties, Knucks, Pans and Shovels and apart from changing the spring between summer and winter, a pretty reliable and hassle free carb
Running a HSR42 on my evo and just changed the idle jet up 1 size due to the colder weather in Melbourne, it would just stumble a little on light throttle on take off and a little pop now and then cruising on low RPM indicating a lean condition, need to swap it back in summer as it gets a tad rich. So my opinion, CV, Mikuni, SU still require a bit of work to fine tune.