Captain America was finally released in 1979 on a skinny body. A buff body might have helped with the huge head he has, but he'd still be out of proportion. However, it was Mego's opportunity to correct previous failings in the costume department. He came with a shield, red glove cuffs, white mid-arms and flounced boots.
Below is a boxed Canadian (Grand Toys) Example of the 12" Hulk, Mego went all out with it's Deluxe Hulk, dig that labcoat! Check the Library for pics of the original prototype.