I have a friend with a 67 GTA convertible (1 of 2112) and he wants to outfit the 390 with a tri-power setup.

I think his biggest concern should be about how he'll fit that thing under his stock hood! You can't use the factory ('oval') air cleaner on a Mustangs, if you're starting with the Galaxie type ('inclined') intake manifold....not unless you modify either hood or air cleaner, anyway. Space is tight under there so something has got to give way. Most folks notch the underhood bracing.

He is concerned with tuning and synchronizing the system.

I hate to sound unromantic but he's worried about nothing. Very little fussing is required for six 'barrels' of fairly typical carburetion.

I suppose he's thinking of Webers, which are (in)famous for being finicky. By comparison, Ford's "3-deuce" system is a snap . He'll need just three things: (1) a complete 6v set-up, (2) a good carb rebuilder and (2) the Ford Shop Manual for 1962 or 1963 Galaxies, because 6v was a factory option in those years. The only trick is in adjusting the progressive linkage and that's where #3 comes in.

Tell him I said to relax and have fun! We sell reprints of the carb set-up pages, in case he wants to skip the Shop Manual. Hope this helps.

Mr F