5/8 in hose coming from each valve cover into a breather catch can. The breather hole that the filter attached to was only 3/8 I widened the hole to 1 1/4 inch and installed a thread pipe and hose clamp breather to that. (I just did that today)
Not sure what else I can do since I have plastic valve covers and can't really get the drivers off without dropping motor down few inches.
Only other thing I could add is a breather oil cap
5/8 hose is equal to -10. If you have one line per valve cover going directly into the can that should not be your issue.
Some of us run -12, but I'm not sure it is really necessary, but more because the incremental cost is only a few dollars vs. a -10 setup.
I also have a braided drain line with a proper drain fitting and real fittings. That picture with the tape measure is not confidence inspiring vs. what you would have a real -10 fitting. That "could" be an issue, but only if it is really too small to accomodate the drain volume.
Let us know the results from your testing before we try to philosophize further on this. What you are doing looks like the right steps.
I'm sure the guys here can help you piece together a drain with better parts if you need it. Keep us posted.
I'm a little puzzled why kits would ship with home-depot like parts. Real AN aluminum fittings and line aren't expensive for the type of setup we are talking about for a drain line.
(not to scare you, but when I overspun my PT78 from too much backpressure it smoked like a train. It twisted up the center and was shooting oil into the downpipe)
1989 Saleen 89-425 all original + Baer 6P Brakes
1990 Saleen 90-137 heavily modded
1989 Shadow Blue Metallic Hatchback LX
-- 94mm T4 True Street Trim
Baer, Haltech, UPR, National Parts Depot, Meziere, Weldon, BBRC