I was just wondering what might help my 351m run better in the summer. Right now it has the stock aluminum filter housing above the carb. I'm using the round K and N filter in it. It has the one inlet to the housing sitting open above the passenger side exhaust manifold. I was thinking about doing something to pull in cooler air. Maybe add another inlet on the drivers side and routing them to the inner fender well? Or maybe routing them to the front of the grill to help force air in as the trucks moving? I wonder if the fender well air would be cooler than the air at the front of the grill...whether the truck was moving or sitting still?
It would depend n the size of the tubing. 3.5" should suffice for a single intake. More than just providing more air, you should look into making the air transitioning into the motor as smoothly as possible. The sharp 90 it's making through the filter slows the air coming in. I believe KN has a device that sits on top of the carb bell and smooths out the air going into the plenum. K&N also has a plenum for carbs where you plumb up a K&N style cold air intake and put a cone filter where you like.
There are a lot of options if your up to a little fabrication. Good luck and enjoy.
The best thing to do is hook the factory cold air tube back up that uses a flexible hose from the snorkel to a plastic connector the was bolted to the core support that draws cool air in from the front of the truck. Hit a local salvage yard to pick up the needed parts.