Cees,
There are indeed tons of upgrades available for your engine. That was the absolute low point in the history of the big block Chevrolet engine. Ignition system is good except needing to be recurved. Carburetor if original is good but few people understand them so seek one out. Much better cylinder heads, camshafts and higher compression pistons available. I would consider simply parking the original and buying on of the many "Crate" engines available directly from Chevrolet.
