I have the same Pioneer car and would like to make a replica livery out of it, and the same goes for the #46 Scalextric Castrol Camaro of Frank Gardner. Neither of these cars actually raced in Trans Am.
Did you strip the Pioneer body or paint over the gold & black and decals?
I know the preferred way to go is soak the body in brake fluid till the paint and decals come off, but the one time I tried that with a Monogram NASCAR I ended up soaking it for 3 days and still didn't get a clean start.
New livery for the Mustang:

New livery for the Camaro:

For these repaints I'm thinking of just painting over the existing liveries, with a grey base coat, and then the desired colors (red for the Mustang and bright orange for the Camaro). Anyone else done that?
Slothead