Hello lineslinger,
I happen to run just the setup your asking about. Pros and cons, well that all depends. How do you plan on using this vehicle ? How much money do you want to spend ?
I can only tell you why I made my choices. First off, I chose a Dart Iron Eagle block. I did this mainly because of the siamese cylinders which allow you to increase the bore size to acheive 427-454 cubic inches if so desired. You can not obtian these cubic inches with a production 351W block without increasing crank stroke, affecting rod ratio and moving the piston pin up into the
oil control ring grooves. Both ways work. It all depends on what your trying to acheive and how much you can afford.
As for Weber carbs I run a set of 48IDA's. Pros - they really add alot of nostalgic, vintage interest under the hood, sound great and have plenty of power/torque to deliver. Cons- cost, more initial time tuning. Once you learn these carbs, tuning them really is not difficult. All I can say is that I am extremely happy with my setup. I can get into more specific details of my build if your interested. What I do know is the setup I do have makes some serious power !!