Radio Help

Nothing protrudes into the dash hole. Don't recall the name, but a generic Chinese "Android Head Unit" sold under many names on ebay and Amazon around $80. Add $20 for a backup camera w/ wiring. Some $300 ones from a name brand come w/ Android Auto, which is a must-have for many buyers in new cars (and/or Apple CarPlay). Tesla owners fuss that their cars don't have it. Problem is the more powerful boxes aren't as thin.

If you have an OBDII engine swap (1996+, say Magnum V-8 or Hemi), you can run TorqLite on the Android to read an ELM 327 OBD and display engine parameters like rpm (if no tach) and codes. I do that in my 1996 Plymouth minivan.