I’m getting ready to put the instrument cluster back in my 69. I’ve read though some past post, but I can’t find a clear answer on bulb type. Bulb number 57 seams to be the correct factory bulb. Since it is near impossible to replace bulbs once the dash is complete I would really like to have a bulb that never burns out. Is there a long life bulb? My only concern would be heat. I don’t want something that will damage the plastic.