The instructions on use of K&W Engine Block Sealer state that after installation of the sealer idle for 20 minutes and do not drive or rev the engine however in several of the blogs it was recommended that the vehicle be driven for up to 500 miles. Which way should I go on this one, i.e. do not drive or drive 500 miles with the sealer?

Go with the manufacturer instructions over what you may read on blogs.

Alternatively, ask the guys at your local NAPA or other Auto Parts retailer (like Parts America, etc.).