PB vacuum hose size?
 

I am putting a street rod together and the fitting on the master cylinder booster is for 9/16 vacuum hose and the fitting on the engine is for 11/16 hose. I have a 11/6 fitting for the booster, does it make a difference? Or Should I change the engine fitting to 9/16 and run 9/16ths hose? The master is under the floor.
Thanks!

Anyone know?

Either size is fine. With the booster under the floor, you should use a filer/seperator in the line somewhere, you can find them on many late model cars.