Filled block on the street?

krazykuda said
Part of engine cooling is to direct the air THROUGH the radiator, not AROUND IT...

Shroud is important. When set up properly, the shroud directs and helps the fan PULL the air through the radiator. You have to seal the gaps so the air does not go around the radiator, but through it.

Another part of the shroud set up is how much overlap the fan and shroud have. One design spec for engine cooling is called FOOS (Fan Out Of Shroud). If the fan is too deep or too shallow into the shroud, it looses some of it's efficiency. Start at 50% FOOS (half the depth of the fan is overlapped by the shroud) and go from there. Usually you don't want more than 20% either side of halfway in at the most (30% to 70%)...

Consider the shroud as a funnel to direct the air through the radiator and fan...

This is 100% correct.

I forget to mention stuff like this because:

1. This information has been out there for DECADES and is more accessable than ever.

2. You can pick up the phone and talk with a dozen different manufacturers on the phone about YOUR specific issues. If you give them straight poop they can almost always fix an issue for you.

Thanks for postings this often forgotten info.

BTW...if you want to see what works...look at a STOCK, UNMODIFIED MoPar fan/shroud/radiator. They OEM system is bullet proof but not idiot proof. I've seen guys break a bowling ball in a sand box without tools.