Quoted from Frogroar:I'm in the process of converting the game to LED, but was thinking to keep some of the incandescent bulbs because I think the visible ones look nicer than LEDs in this game. Everything under the playfield and in the back box will be LED though.
I recommend replacing all 44 and 555 incandescent bulbs with LEDs. There is an alternative option besides LEDs, which is Comet Pinball's SMD retro bullet bulbs. They look and produce the same amount of light as an incandescent, but are efficient as a LED bulb.
https://www.cometpinball.com/products/retro-smd-bullet-bulbs