There are 76" dia props running without issue on -7s, -7As, & at least one -8 powered by rotary engines. Surely the dia won't be an issue on a -14.
As to speed, the larger dia will definitely improve takeoff performance. And IIRC, when you run the numbers on rpm/dia/airspeed, you have to get a fair amount faster than 200 mph before getting hurt by a 76" prop at Lyc rpms. If it's c/s & you're running down at 2400-2500, like most seem to do these days, the larger dia should have unmeasurable negative effect at speed. For perspective, a Cessna T-210 cruises at roughly RV-speed (faster at O2 altitudes), and runs an 80"+ diameter prop at 2600 rpm.