Rad air flow direction
 

Just set my first dual AMD XP rig with 2 Gemini normal flow WB, Gemini northbridge and GF3 WB. I'm using Eheim 1250 pump and a new 87' Ford Bronco heater core ( 6 1/8 * 7 * 2) with 4 92mm Panaflo (volt modded) push/pull array. I also have 2 80mm Panaflo at the rear exhaust.

My problem is I don't have enough rear space so I have to put the heater core at case intake. Initially I set front fans inflow and rear fans outflow, but I found the motherboard temp shooting up and CPU temp is not so good either (MB 38C, CPU 46C). Now I changed to front outflow and rear fans inflow, seems better. But I'm a little bit worry about air turbulence and it may not be efficient. Does anyone has same experience in this kind of issue?

First, wow, nice hardware.

I'll skip a long theoric debate and say: do whatever is best for you. Try to switch air flow directions and see the results.
As a reminder you'd want to have *slightly* negative pressure inside the case, and most fans *pulling* through rather than pushing.
The other thing to consider is hot air rises.