Are they worth any power on N/A engines?
Seems I read Reher-Morrison was claiming 30-60hp on N/A engines in the 900-1000hp range....

For sure worth real power.

They are worth a good amount of HP when coupled with a vacume pump, and low tension narrow ring pack. You would also want a different bore finish...TotalSeal rings can set you up with what you need there, and then just have the pistons ported.
I prefer lateral gas ports most of the time, unless it's a true drag engine that will be freshened often.

All things being equal...if you changed nothing but going to the gas ported piston direction how much, if any, would it change the lean/rich tune-up? Sorry for the requested simple answer to a probably complicated question but...guess?

Well my are already purcashed, and they do NOT ave gas ports.
Here's the deal, my machinist doesnt have a hone/torque plate for a large bore Hemi. This guy does A1 work, and he is considered a good friend also. I was thinking, that have a so-so hone job, that the gas ports would make up the diff and maybe then some.
He explains to me that the Hemi although benefits from a Torque plate, he is confident in making good ring seal without. He said some engine really need them like small block Fords etc.

OK
How much does it cost to have a set of piston machined for lateral gas ports?
I figure $150 range...but I dont know.

To be honest, you'd probably be better of spending the money on a torque plate...

IMO proper cyl wall finish is one of the most important things on a high compression engine

RPM plays a major role in the question of does my engine need gas ported pistons...

I should say piston speed, so if you have alot of stroke (4.500) and plan on 7000rpm, then I would do the gas ports, and change the ring's around. But without the vacume pump, it'll be alot of money spent with little gains.

It all needs to be done to really see the big gains.

Gas ported pistons, low tension rings and a vacuum pump and 28 more cubic inches made my car .25 quicker in the 1/8 mile and 6 mph on the 3rd pass in the car. Haven't even started playing with the carb or timing yet. Plus adding over 100 lbs to the nose of my car. Just my