Google ‘slant six HEI ignition’ there are probably six billion threads on the internet that address that common conversion.
Please don’t take this the wrong way, as we all have to start somewhere, but Pishta and others have provided sound advice and then you trip up on some of the most minor details.
Just an idea, consider instead of building a low budget turbo slant, just do a low budget stock internals rebuild on the existing engine. You can put in a turbo friendly cam, maintain turbo friendly compression, put a Holley 350 cfm carb or a super six carb or a MSII with MPFI and get yourself some engine building and engine tuning experience. After you have your arms around that, then think about adding the turbo.