Flathead man2, I can see from your posts that you're new to this aspect of the hobby. I dont mean that disrespectfully, we all started at the beginning.
My best advice to you is ..... "some fella told me" ..... forget that, the fellows on this forum are collectively the most knowledgeable in the world. Some guy down the road who has only ever had Chevys or some such likely is talking through a hole in his head. Some things you should know....
* There are many ways to do something, and many opinions. Assimilate them all, and go with what seems to you to be the best plan.
* Rack and pinion is not traditional, and does not work well with a beam axle.
* Disc brakes are not traditional to the 40s and 50s, but ARE to the 60s.
* Most projects either fail, or do not look good, because the builder did not stick to a theme. If your theme is 40s it will be a little different to the 50s, but a LOT different to the 60s. Do not mix and match, it will look half-arsed. To this end you need to do a lot of research and decide which theme is for you. My project is a 50s theme, and any bits on it that are not "right" are out of sight.
* Read everything you can, both on here and on the HAMB. Between the two there is everything you will ever need to know.
* Regarding triple manifolds with dummy carbs, there are some narrow-minded folks (mainly me) who regard such practices with some disdain, a bit like the guys who put Olds Rocket rocker covers on a Chevy. They aint fooling anybody who knows a thing or two. Dummy carbs are always cleaner than working carbs and stand out like a .... well, a dummy carb. Go with two carbs or a four barrel. Triple carbs are too much for a stockish engine, but can run OK on a big incher.
* Motor City Flatheads will I'm sure be wonderful engines, but you can get a brand new French block from Sacramento for a fraction of the price. If you want someone to build you a motor and you have some bucks available, give H&H Flatheads a call. Building flatheads is what they do.
* All of the above is purely my opinion based on decades of building and running flatheads. Take it or leave it, your call.