The depth is around 1 3/4" to inches from the bottom of the magnet to the mounting flange. This depth will be sufficient for clearance between the magnet and the top of the Speedo/Tach cluster.
I just replaced my front dash speakers in my '81. The originals were long gone, and the ones I pulled out were old Alpine SPE-4620's. My replacements I bought are Eclipse by Fujitsu Ten. Model #84641A 4x6 2-way coaxial speaker. They were around $100. The sound and output was very good in my opinion. Hope this helps you out a little.
cmegga, is that measurement the over all depth of the speaker?
Or is that "mounting depth?" I know my over all was about 2.25 inches. If I had a "mounting depth" of 2.5 in. I would never have set my gauges back into the dash without the magnet hanging in the way. The glove box side is no problem. I must have the "thinner" dash........????
drsantos, sorry to use your post to reply to another member. But I felt like the member above "stepped on my toes" a little. So I'll be spectating CAC, not adding my .02 cents anymore. Again.....my apology.