Those carbs can be a lot of fun to play with for anyone enjoys tinkering and improved performance,a little tricky with a high end cam.it may be difficult to achieve BOTH a good idle and great acceleration.Make sure you have adequate exhaust flow.
I couldn't agree with Jack more as he says,

"The most critical thing to know about SUs are that they are entirely dependent on the condition and tune of the motor. You will never get the SUs right if your valve lash is out of spec or your timing is off."

I would also check dwell and if you are still running a point type distributor,then you should seek out an HEI system from a mid seventy's heap,I believe there are still quite a few of those out there in you neck of the woods.
peace