I have the aluminum one, and will be switching back to stock. (I'll use this one on my other motor) It has a leak now, and next time, I'll polish and seal it. I may also tap it for the PCV as I have a threaded baffeled one to use when I do. I've had some problems with building too much pressure at points (usually Higher speeds) and spewing oil out where ever it could... so I'll clean things up and switch back and see if that fixes the leaks and the uneven pressure?

Some have said that if you run breathers in both valve covers it helps? But I like mine to look kind of stock until you really start looking...

Brett - 67 Drop Top 455!