For the oil pan, There is a 55 Ford Pick Up made By Monogram, in 1/24th scale.
It has a Cobra oil pan, and valve covers. I'd take a pick, but I don't have a camera right now.
Also if you do a web search, for scale calculators, (there are several out there) you can usually input your size, select your scale, and it will tell you what size needs to be. click here Hope this helps.