Spouse of Raven Mad here and I work in the wholesale electrical supply trade.
Yes, you are correct the T12 lamps are gone by federally mandated energy saving mandates.
As for your question, yes the pin spacing is the same BUT the lamps are NOT interchangeable.
The older T12 lamps run on a 40 watt output core and coil ballast which is very energy wasteful.
The T8 lamps are 32 watt and run on electronic ballasts that are very energy efficient.
If you have a quality fixture in your garage where the ballast can be replaced you can put in a 32 watt ballast and the T8 lamps and get a brighter light for less power usage.
If your fixtures have the ballast built into the frame the fixture will need to be replaced. These are usually cheap imported fixtures.
If you do replace the ballast(s) please follow the wiring diagram printed on the ballast because the T8 does wire differently from the T12 style. The wires in the tombstones (lamp sockets) can easily be removed by sliding a paper clip in next to the wire and pushing on both at the same time, the wire then will easily pull out.
Always de-energize the circuit for your safety and so you do not damage the electronic circuitry in the new ballast.
On average it will cost about half the price of replacing the fixture to replace the ballast and install the new lamps.
Lamp color: your old lamp is a "Daylight" in color output. The color output is slightly blue as compared the a standard 100 watt bulb. To match this same color with the new lamps you need to purchase lamps in the 50K color range.
Common nomenclatures are FO32/750/ECO by Sylvania, F32T8/SP50/ECO by GE etc. As long as there is "50" in the number on the lamp you will get a very similar color in the room.
I hope that this is helpful.
Roady Rider
{{{raven mad here - you'll do best by going to a locally owned electrical supply house! They know their stuff, and can pull the fixtures/ballasts/lamps for you, instead of you having to hunt them up. Just DU-mail or reply if you need more info!}}}
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