[Drake] Cooling fans - blow in or out?

[Chris Codella, W2PA]

I'm about to install a cooling fan on my T-4XB and TR-4, having seen 
many ways to do it.  But what's the concensus on the list about blow-in 
vs. blow-out?  I've seen it recommended both ways.

The only recommendation I saw that also included a rationale was one 
posting where someone said to orient the fan blowing out because the 
only time one wants to blow in is if there is a forced-air handling 
design built in, as exists in many amplifiers (i.e. chimneys, etc.).  I 
must say that most rigs I see with factory mounted fans on the back that 
also don't have air handling features inside, do in fact blow out, not in.

What's the concensus among the Drake crowd here?  Please don't recommend 
one way or the other without giving a reason.

Thanks!
73, Chris, W2PA