[brucepick]

Nice belly pan work!!

Looking at the big cutouts for the front wheels, I think there's probably plenty room for air to exit the engine bay.

HOWEVER it might have to go all over the place to get out that way - so a nice opening in a location that's 'convenient' to where the air flow wants to go, might be a good idea.

Closing off unneeded air flow through the grill is a good idea - the question is, which air flow is not needed? See notes below.

If you have (or get) a ScanGauge you can monitor engine temps digitally which is WAY better than watching a gauge. That will tell you if your grill block is causing higher than normal temperatures. Otherwise you have a good chance of choking off the air flow so that your radiator fan comes on more often to keep the engine from overheating.

It wouldn't overheat (hopefully) and your gauge will likely stay at center - but you'll be running the fan a lot more than the designers intended. I know because I've been modifying my grill block and monitoring engine temps exactly that way.