Ah Webers!!! Yes, I am familiar with the sickness. Lots of bucks and a sorting out process. But once done, well, they run sweet, and nothing else looks quite as purposeful. Always a crowd pleaser.
It's clearly a little more of a hassle on a 351 as you either have to put spacers on a 289 manifold or track down one of the handful of 351 manifolds around.
In any event, I would do it again. In fact, I plan on it.
Just do it.