You can buy a pop off valve and install it on the cover or just get a rubber expandable freeze plug and use it in your existing stand pipe. in either case when the engine is sealed to pull vacuum, you need a way to relieve the pressure in case you burn a piston or blow the head gasket into the valley,otherwise the oil pan will be destroyed from the pressure and you will get an oil bath on the tires.Bill

gimmimud that's some funny right there about the cam lol. if you run to much vacuum it starts pulling oil away from the wrist pins and sides of the bores and thats not good. i never set them up with anymore then 14-15. the vavle covers or the intake is about the best place for them. i think they are a little more accrate in the intake but most put them in the vavle cover.

Thanks for all the help guys.

I agree with topsportsman1 12-15 inches unless you have piston oilers.
Your on the ragged edge at 9600 ,thats 6400 FPM piston speed and probably way past the power band.try taking enough gear out to drop the rpm to around 8000/8200 I bet you will be a lot faster and for sure the engine life will increase a bunch