Hello Manuel

            I repainted some McCoy Redheads many years ago as basically an arts and crafts project. I never started the engines after painting them. I sandblasted the worn and faded paint off and fogged on a very thin layer of paint and put the head in a kiln at about 110 degrees. The idea was to SLOWLY accelerate the evaporation of the solvent before fogging on the next coat.

            Dupli Color engine paint is still with us and shows up on Amazon. The chipped paint is due to many years of hangar rash from being stored in a shoe box and moved around. It may be OK for display purposes but don't know how it would stand up to normal use.

     Ara

It is my belief that the K&B's and cheap McCoys used enamel on the heads, probably baked after some atmospheric drying time. "Baked" would probably be no more than 140 degrees Fahrenheit...which would be around 45 > 50C. Inside a hot car during summer would be about right.

As an alternative, the fishing industry here has kits for DIY powder coating of jigheads and such. I have not done it, but the procedure is to dunk the head of the lure into the jar of powder, then put it in an oven...temperature unknown to me, but probably not terribly high. I'm not sure what colors would be available, but would suggest searching online at Bass Pro Shop, Lure Parts Online, or Jann's Netcraft. BUT, you won't want to pay to ship to Spain. You may find similar stuff over there, somewhere closer and less expensive to ship.  Steve

https://www.basspro.com/shop/en/pro-tec-powder-paints-for-lures-or-jigs

https://www.lurepartsonline.com/Stamina-Powder-Paint?quantity=1&custcol_beads_eyes_paint_size=157&custcol_beads_eyes_paint_color=115

https://www.jannsnetcraft.com/powder-paint/381100.aspx#ItemImage

VHT High Temp Engine Enamel is a color match for McCoy Red Heads...SP121 Bright Red.  It contains ceramic and says good for 550F/288C. I've used it on several McCoy RH engines and you have to follow the instructions to get a hard factory like finish. It's held up well with 10% nitro.