Not that I want to confuse you, but a couple of different ways to look at your "problem":
First, the 250 L6 is a very good engine, reliable, which can be improved, either just aesthetically (aftermarket intake/header, valve covers...) or performance-wise (camshaft, carbs...). The 250 can easily be just as pleasant to use as a mild small block. I would thing that removing the emission stuff is easier than swapping in a V6, even if you need to ask a few questions in a forum.
The TBI injection system (with its dedicated distributor) is an excellent system, dead reliable: keep it! Simple, it will last for ever and will run really smooth (smoother than a carb).