Welcome, It's always good to have fresh minds.
When you say "modernize" I'm not sure where you want to go. Most modern would be the 4.2 Trailblazer DOC 275 hp engine. Sorta' modern would be the 250-292 '70s-'80s engines and Classic updated would be what you suggest for your 235. Updating/modernizing the 235-261 Chevy engines and the 270-302 GMCs is more fun for me. But I'll be 72 in a few days. The important question is : What will you really use the car for?. Answer that question honestly and the rest will fall into place. There is no "one engine fits all". That said, there are a lot of more modern mods to be made to the old engines than are in Bill Fishers 1954 books.
