750 cfm carb on a 318

A little large, for a teener, but
If you already own the 750, install it ,spend a couple of days tuning it, to satisfy your curiosity; then put the 600 back on. But I wouldn't rush out to get one.
A 650DP? Well,now you're talkin. Ilove DPs.
You might need a side of gears to go with that.