Open the drivers door up and look in at the door jam and you will see a sticker with that info on it.
The 2006 Chevrolet Silverado-2500HD has a V8 engine.
The 2006 Chevrolet Silverado-1500 has a V6 engine.
The 2006 Chevrolet Silverado-1500 has a 4.3 L base engine size.
The 2006 Chevrolet Silverado-2500HD has a 6.0 L base engine size.
P245/75 R16 Chevy stock size
2wd or 4wd?
235 75 15
Stock size is Standard 245/75-R16 Stock option size is 265/75-R16
That would be the 4.8L engine.
6.5" in the doors. Standard tweeter size (1.25" I think).
The 2014 Chevrolet Silverado-3500HD has a V8 engine.
The 2013 Chevrolet Silverado-2500HD has a V8 engine.