Hi Rick, and
I've not heard of an SU conversion although I can't see why not as in the UK they seemed to be almost equivalents, a bit like the Dellorto/Weber thing. Having run cars with both SUs & Strombergs, I have a personal preference for SU which is nothing to do with performance, just that I think they are a simpler design that works equally well. From memory the critical things were to centralise the jets properly to allow the main piston to move freely both hot & cold. Apart from that they were pretty much "set-up and forget".
Tuning-wise there are (or were) a standard range of jet sizes with many needle options, the differences in the needles being the gradients/diameters along the length to allow differing mixture strengths for any given height to suit where your cams/engine/ignition advance needed more fuel than a slower cam/etc.
There are a few good reference books out there, a quick search on Amazon will no doubt bring up a page full. The one I had listed all the dimensions of the jets & needles together with typical applications, which made it quite easy to get a start point when installing SUs on an engine that didn't previously have them.
Brian
