Im pulling the fender wells out of my car and painting the engine bay side with JD Blitz Black, what color or undercoating do you put on the wheel well side?
3M™ Body Schutz Rubberized Coating Black
Part Number 08864, 3M ID 60455047294, UPC 00051135088647
applied with a (*3M or aftermarket) special Gun, I would recommend staying away from the aerosol versions if you can.
For the Engine Bay side it was recommended I use Krylon Industrial Acryli-Quik, Semi Flat Black K01613A07
Search the forms here & you should find Lots of recommendations
JIM