Use liquid teflon!!
Joe the builder at Shelby Engine Co has built hundreds of FEs and this is what he uses. I tried it and BOOM it worked.
https://www.amazon.com/Rectorseal-Tr...gateway&sr=8-8
I still have a leak around the base of the adaptor. I have tried everything, I think I will try this
www.HYLUBE.com- Remote Filtration/ Wet Sump Systems- Chatsworth, Ca.