Slant six single, to slant six double.

MidnightSwinger said
I’d go with an Offy intake with a 2bbl Holley 2300 in the 350 cfm variety.

Any other aftermarket intake you will either need headers or a block off plate for the stock exhaust manifold heat riser.

I intended on picking up a pair of aussie headers as well. They have the long tube ones. I know people swear by the durtas but not a fan of the look.