You want to cut as small a hole as possible. Otherwise o-rings won't seal. What nuts came with the fittings? Standard nut is just that. Other type has a recess that really helps to keep an o-ring in place. The steel washers also help position an o-ring but not as good as the recessed nuts. Problem is the depth of the threads on these large fittings make for quite a gap between any washer and the minor diameter of the fitting. Then there are the Teflon washers. Use a sealant to seal it up to the pan and to the nut. O-ring helps to keep the pickup from sliding around. You can't tighten up against the Teflon very much or they will break. Actually they will break anyways,just not as soon. In the end you need to find what works with your pan. And don't forget,these will leak thru those threads. Myself,i use nothing inside the pan. An o-ring with a fair amount of silicone on it and a teflon washer with a sealant on both sides. Not silicone. Snug it down and let it set up overnight. Running external lines on 3 cars and no leaks. I also keep a stash of Teflon washers handy. Anyone come up with another way post it up here as I want to hear about it.
