318 LA rear main leak?

I checked the clearance with plastigauge today & it is .015 to .020 clearance so the cap is clearly sitting correctly.
I spoke to my machinist who tells me that indeed the do not sit flush or bottom on the block
I too did the paper trick like Bobzilla shows . I think I will just replace the rear main with a felpro bs 40245
It had a victor prinz vdc po5404 &8403 in it & thread tape on the rear plugs that were not leaking nor was the rocker covers or oil pressure switch as they were checked initially
Thanks for all your input that's why I love FABO