I am a newbie Ford truck owner. I have had my 1965 F100 for about 3 days...

I've never been very mechanically-minded, but I want to learn; and the simplicity of this old Ford seems to be a good place to start.

The engine is a straight-6 240 CID (according to VIN info). Everything looks pretty stock, with the oil bath airfilter on the carb, etc...

I am smelling exhaust fumes in the cab, so it seems like this will be the second job I tackle (the first thing is to put better tires on it).

I'm looking for suggestions for the straight-6 240 CID:

Headers vs Stock Exhaust Manifold (or whatever you call it)
Mufflers (what type)
Dual Exhaust vs Single Pipe

I am thinking that I will replace the exhaust system rather than try to track down a leak. The current tail pipe actually ends directly in the middle of the truck and just in front of the rear axle area... I'd like to run the pipe(s) to the rear and the side behind the rear wheel.

Much appreciation and thanks for all your expertise,
Daniel