That's what i use cast alum valve covers, And another thing i do is you know the front and rear intake gaskets, Well for me they go in the trash and i use axle sealer tough stuff :!: :!:
Shoot you have to pry my intake off, I bet after it set's up you could run without any bolt's in it :!: :!: I use the orange axle sealer matches engine color LOL :!: :!:
I hate leaks too. Mine doesn't have any leaks and it's a mud racing truck. It does have little oil to slosh out of the dry sump breather. I've got one of the breathers with the half hood around it so it keeps the oil off the headers.