...and WAL-LAH...
It's voila, and it's a French word. Honestly; you 'Merican's....
Ted- I don't know if, with your engine, how much difference 1.25's would make. Are the heads on this engine ported? If you have the rockers, then it would be interesting to find out, but I suspect the carbs may not let the combo reach it's potential unless they have bigger venturis installed. Stock vents in kadrons are 28mm, and I would think your engine could benefit from 30's. Once you have it running well, figure out how where it peaks in 3rd gear; remember that it will rev higher (500?rpm), but you want to know where it makes the most power. With the W110 it should go to 55-5700rpm; anything less and the carbs are holding it back.
What happened to fire breather you were looking at? I thought you'd bought it?