I've run into the same problem with our old dyna.
I cleaned the areas really good with citrus degreaser, then masked around it and primed / then repainted it. You have to wipe off any excess that gets on engine fins, if you want to spray between them.
It worked wonders, the engine looks new again.
VHT WRINKLE PLUS™ COATINGS
VHT Wrinkle Plus™ combines strong colors with a deep rich texture for a custom look. It is temperature resistant to 350°F (177°C) and is ideal for adding a touch of personal styling to almost any metal surface. VHT Wrinkle Plus™ resists color fading, grease, degreasers and severe weather conditions. This tough durable finish is extremely resistant to rust, corrosion, chipping and cracking.
Temperature: 350°F (177°C)
Applications: Valve Covers, Metal Dashboards, Glove Boxes, Starters, Door Panels, Shifters, Alternators, Firewalls
Dry Time: Dries within 24 hrs.
Curing Wrinkle Plus
VHT Wrinkle Plus only attains its unique properties after correct curing.
•Bake at 200°F (93°C) for 20 minutes.
•The inherent heat of engine operation will also accomplish curing.
VHT provides a multi-high performance coating system for the ultimate in protection and quality. This system includes surface preparation, primer and paint.
Wrinkle Plus™ Color