When I did my restoration from 1987 to 1990, I glass peaned all the aluminium parts such as the fuel pump, carb exteriors, thermostat housing etc. Glass peening is like sandblasting but I used tiny glass beads. For the one I did recently I used a fine alumina grit in a blast cabinet. The parts come out looking like new like you saw at those car shows. Now after 16 years, mine still look like that. About 3 times a summer, I go to a coin car wash and use the foam followed by the high pressure water blast to clean under the car and all the stuff you see in the engine compartment. It only failed to re-start one time and then I found that the high pressure water spray had knocked the hi-tension lead out the top of the coil. A second later it was running normally. And it's still as clean as it was 16 years ago, even with 94,000 miles since I glass peened them.
At TRA, last June in Ohio, I took 2nd in class in the judged concours. It's easy to keep clean once you know how. See to attachment as to how my carbs look now after all this time and 94,000 miles since it was restored.