if i were you id find a different set of heads and use those heads for another build.
those heads deserve to be in a pontiac!
i have used #16's on a 030 400 ci and finds that all you need is a really great ignition system. i ran a 308 dur cam with 515 lift and if i remember correctly 116 lope desperation. a MSD 6al with a 6k revv limiter performer rpm intake and a mighty demon 825. ran killer! i had it in a 68 tempest vert (which weighs the same as that cutlass) and doing 40mph, i could drop it into 2nd,sidestep the clutch and stay sideways for about 40 -50 yards.
until a rod bearing finally let go.
in short, if you want just a mild engine, use a set of 6x-4's a bit bigger combustion chamber and you can still put the 1.77 intake valve in.
then any cam you pick will not *PING*