just recently i noticed that the front bumpers on a gas and diesel chevys are different. What is the point of that, do the big air hole's do anything for you? I was also wandering if it is bad to block the holes with lights or something?

I think it's to help airflow. I know when my truck was new I had it in the shop for some warranty work and the mechanic told me not to block those holes. I see a lot of them with fog lights mounted in there.

I heard it had to do with pressure, and getting more air to the radiator. Ours also has the block heater plug in the one hole. I think the holes look cool.

I have a heat exchanger for my wta intercooler in one nostril and my PMD in the other nostril...

I agree that the holes do look alot cooler than the solid bumpers on the gassers, but then again diesels are just plain cooler than gassers too.
dido on the block heater plug, thats the only thing i use the one hole for.

The holes are just for air flow but I dont see them doing much. Just look at all the crap in behind them and those cheesy little pieces of plastic the factory stuffs in there. I'm using mine to provide airflow for my soon to be intercooler. I'll post pics in my garage when it's all done!

Ditto on the air. Along with thats were a lot of guys are putting their remote pmd in the bumper hole.