The bulb itself is a T-Series instrument cluster bulb. Attachment is similar to the ones seen here:
http://www.vleds.com/bulb-type/instrument-gauge-cluster/t3-t4-t5-neo-wedge.html
Now, that being said, you can see that the shaft length (hehe....shaft length) is different on the stock bulbs. So what that means for you, is, its time to go custom. You have to take the stock bulb and replace the incandescent end with a proper 360º LED bulb. Instrument clusters are difficult because of the light dispersion. If you don't have a consistent 360º light pattern you'll end up w/ hot-spots on the gauges and light won't look uniform. At all. My first run on these was in my Mustang, and it did NOT turn out well. So suffice to say, its going to require some ingenuity on your part to get it right.
These are the only bulbs on my truck I haven't converted yet (w/ the exception of the turn signal indicators). Because of the time and patience required, if you need to use your truck in the meantime, I'd suggest getting a spare cluster and HVAC pack from a junkyard so you can bench test and perfect the lighting scheme.
