Never heard of that particular model, but when I did a Google search, a number of hits did come up. Some of the vendors also buy Weber carbs, if you decided to sell (or you could at least get an idea what $$ you may be able to ask for in private sale)

I'm running a Weber 32/ 36 DGV on my '68 wagon (stock, no performance modifications) and have been pleased with the results. Good mileage, reliable, and decent performance. I'm assumming that a good condition SU would outperform the Weber however.

Have to mess with the jetting a bit sometimes to make it run really well, once everything was dialed in, I never have had to tinker with it since.

What kind of manifold do you have on your car (is it seperate intake/ exhaust, or combined as one unit?)