How would you mate the two halves of a tunnel ram together?

http://www.summitracing.com/parts/EDL-6999/

i have used black rtv may not be right but it worked for the time i used it, if i had had some more time on my hand i would have ordered those gaskets instead :)
some of the old edelbrock streettunnelrams where smartly designed since some of them used the same plenum and therefore the same gaskets:)