There is no advantage if you are using the original bellhousing mounts. If you were converting to an automatic transmission that uses a rear mount, the center mount configuration would be recommended. Many 350 engines have the front mount locations drilled and tapped to use the early configuration. Replacement crate engines are also set up for the front mounts.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine