im workin on a pontiac trans sport van,

just put new fender on it, new bumper, new axles, etc.. was in a wreck.

everything works now and it runs strong but smokes... what would be the cause of this? should i change all the oil out and put a new filter on?

any help appreciated, also the battery seems dead but i jumped it and it came right on, shold i just let the engine run for a while?