Lawrence.
A lamp is designed to run on a specific voltage. In your case 82V for the 67 series enlarger or 24V for the 23C. You cannot interchange the lamps, the lamp for the 23C blow out immediately if installed in the 67 and the lamp from the 67 would barely light.
The Wattage is the amount of both light and heat the bulb will deliver. The higher Wattage will result in more light AND more heat. It's possible that 300W is too much for your enlarger. There should be a data plate on the enlarger that tells you a maximum Wattage and that is what you can use safely. Higher than that and you may start melting things like mixing boxes and any plastic parts near the lamp.