Hey there,
I have my furnace and water heater in a closet in my home. My home is approx. 1000 sq. ft. and has a crawl space. There is a vent on the floor which is supposed to provide makeup air to the furnace and the water heater. The vent looks like a standard floor register and I think it is six or eight inches long and two inches wide with the adjusters taken off. Well this weekend I am going to tighten up my crawl. I mean air tight!

This is what I understand and plan on doing. I will need to run a vent to the outside to provide good makeup air to my furnace/water heater. I was planning on running a six inch line to the exterior wall and putting a hole in the wall and a vent on the outside with a screen on it to keep bugs/mice out.

Based on the info. That I have provided here, do you think this will be sufficient?

Do I need a draft regulator? I was going to put one in to help keep the air out but I am confused how they work. It seems that they keep air from going out of the house and let air in as needed, depending on how the weight is set on them.

Thanks for reading and any response is greatly appreciated!

Not sufficient. You need to take 50% of your air requirements high and 50% low according to the code. If you have a attic I would drop a pipe down into the room from there then also run a low vent to the outside.