Your best bet is to use a gasket. Slant Six manifolds can be tedious to install, no sense in making it any more tedious than it is. Clifford and Remflex are both great options, but they are the most expensive. Mr Gasket #320 was another option, but they seem to be hard to find now. Fel-Pro will work fine, and the price is right.
I believe your best option for what you want to do is the Napa Mahle MS16030 Should be around $10.00 and is an excellent gasket.
