I couldnt find a forums to post this in. Would it be a good idea to primer my engine bay with spray paint primer and than paint it with a spary gun? Is their any downsides to this and what would be a good primer to use?

 

you shouldn't mix products but as long as you seal with the same brand/type of sealer as BC or SS you are using you should be fine.

 

Some spray cans are compatible with spray gun stuff. Some arent, if it isnt it'll boil.