I intend to bring my type 4 cases somewhere to get welded.

What is the best method to weld a case?

Tig, mig, other high tech method?

Our guy tig’s them.

So old oily cast is a nightmare no matter what. You want someone who has a technique that works for them. It's less about the weld medium and more about the prep and approach.

What company do you work for?

Rich

Had a crack in my case. Chris Foley repaired it and Ed Morrow and Chris came up with a clever solution to a leaking main gasket post welding.
You might contact Chris.

My own company - The 9 Store.
I don’t employ the welder. He’s someone we send the engines to, to be welded.

TIG and I can do them if need be.

The only reason I don't use Ben is because I can drive the engine to our guy vs shipping. Ben has welded a bunch of mag and aluminum parts for me and I'm always pleased with the results.

Are you still thinking about that flat 8?

Having recently needed Tig welding done on CIS aluminum intake arms, the key was to ultrasonically clean the aluminum. Any fuel or oil vapor will poison the weld. We had a little learning curve on how to get all the years of fuel impregnation out of the arms. Once they were "clean" they Tigged up nice.

It’s time

Just bake them and that does the same thing. I honestly do this type of thing daily.
Cleaning is the key though to your point

I would consider hiring Ben, at least for consulting

I may just do that.
First I need to get everything milled and jigged up
Supposed to be super cold this weekend….so I will stick by the fire till that is over.