Inliner help is all racing stuff,like Hotrod says,a street engine may encounter problems at part throttle that's of no concern for a limited powerband racing engine.A top Inliner told me I can't build one properly, good enough reason to make one then wink
I know Leo Santucci pretty well,he really doesn't have experience other than drag racing.But he thinks it's possible with some thought.
Looking at Offenhauser,and the old manifolds from Thickson etc, they are simple castings,a common log plenum, short runner for the intake ports and 2 or 3 or 5 carb mounting flanges.Doesn't look like rocket science to me.Lots of guys run these manifolds, I had multiple carb experience on a 261,was no problem.
I can buy a 3 carb cast manifold from the newly formed Wayne Co for a nifty 450 bucks, or I can weld one up for 50 bucks.The worst it can be is wrong,right?A good experience either way.