Obviously the biggest gasket areas will need the most attention. The oil pan should have a thick and true rail and have all the windage tray stuff built into it instead of a sandwich type. The valley pan area is probably the hardest thing because with aluminum heads you are entirely dependent on the beads of silicone down the sides. Using a Jesel belt or a Milodon gear will help the front area big time. The distributor hole is also a challenge. Pull as much as you can and hopefully you can get north of 10 inches. High quality silicone like "The Right Stuff" will seal well but I've read here that it is a challenge to remove. You should be able to see anything that needs attention with 10 psi max. of pressure. Don't over do the air pressure in the crankcase. Post up your results! FWIW, I have seen 8-10 inches at the finish line (72-7,600 rpm) with my little 493 with the above mentioned stuff on it.