Pistons and liners are usually different between turbo and natural Detroits. The compression ratio, sometimes port height, and probably where the rings are on the piston.
Head casting may or may not be the same, valve seat inserts are different, usually the valves, and sometimes springs too.

While you could just add a turbo to an N engine you'll have better long term results by starting with a real T engine, especially if you plan to work it hard.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-