I have finally laid hands on a triple sidedraft intake manifold for my dear old 69 164 that I got 40 years ago. I am planning to use 3 HIF6 carbs with it and B30E/F exhaust manifolds. I found that the manifolds do clear but not by much. Also the exhaust manifold flanges are about 0.160" thicker than the intake manifold flanges that share mounting bolts. It looks like the best plan is to plane the exhaust flanges down on the gasket face (unlike what I have done on B20 manifolds) because this will not only make the use of half-washers unnecessary but will also move the exhaust manifolds closer to the engine, increasing the clearance between intake and exhaust manifolds.
If any of you have experience with this setup, I would admire to receive the benefit of your experience.
BTW I am planning to use the IPD Street performance grind and 1975 B30 electronic ignition and dual exhaust to something approximating the stock FI front muffler.