I'm 2/3 done with the dry sump install. I'm doing things with the PCV just slightly different from Chad. He tied the the two vents on each valve cover together. I'm not going to do that. Instead the back vents will remain stock, the front vents will follow the path Chad is using: Front Vents to a Tee, from Tee a short hose to another Tee. That Tee is tied down to the old PCV block fitting, and on to the tank.
Why am I keeping the back vents stock? Well for one thing, simplicity. The back vents are tied together by a pipe and hose that has a Tee in the middle that goes down to another block vent. (Not the same as the PVC Block Vent). This plumbing is not connected to the Intake system, it just goes from one head to the other with a Tee to the crankcase. Less installation time and effort.
But the main reason is what I read in the Perrin AOS installation instructions. They say that the back vents and block are tied together to balance pressures between both heads and the block. They are explicit that this balance system is not to be modified or removed.
Does it matter? Probably not. Chad's system should balance anyway since his method ties the old PVC vent and the two heads to open air thru the tank and vented catch can. So the block and heads should all be the same pressure, or come to equal pressures very quickly.
One other possible benefit is if the heads fill up with oil in a turn and start to back up the hoses, the stock balance system is lower and shorter than going all the way to the tank, so the oil should drain from the heads more quickly.
And for those of you looking at getting an AOS: My Spec B had a Crawford AOS and after the motor blew I discovered the FMIC and all the intake tract had a ridiculous amount of oil in it. I've downloaded both the Perrin and Crawford AOS installation instructions and IMHO the Perrin instructions are far superior, and it appears the product looks superior too.
I'll post up some pics of the dry sump in operation, hopefully by Tuesday.
EDIT: After seeing Chad's post about air in the oil I'm rethinking running a hose from the crankcase PCV vent to the hose that comes from the front head vents to the tank. Now I'm thinking I'll just cap the old PVC crankcase vent. The crankcase should still get enough air to avoid problems because it will get air from the front head vents> inside the valve covers> to the rear vents and into the crankcase via the rear vent balance system.
At least that's the theory!