Fan positon on heater core

I am redoing my heater core setup. I currently have a bonniville core with 2 120mm pull fans. In my new setup, I was going to put two more 120's on, but here is my question.

Should I go push-core-pull or stack the fanns and goo pull-pull-core

I would say go with push/pull. I know when I went from push or pull to push/pull I saw about a 1c imporvment. I had to ask myself was the extra noise worth it.

kind of off topic but for a dual HC and 2 fans, push or pull?

suck offers a little more heat transfer, like almost non-measurable amounts. And personally, I like the fact that the sharp part of my fan's spinning blades are facing the heatercore and not me....

So your saying that it isn't worth the extra fans. What I had planned was instead of running 2 at 7 to 12 volts, I was going to run 4 at 5 to 7 volts.

I am building a new cooling box so I want to make sure I get the best arrangement possible.

No, I'm saying that
suck&blow>suck>blow
and, of course use a shroud. Both sides if you have fans on both sides.

i am going to a w/c setup, i am going to have a dual heater core for 2 120mm fans, and they will be in the "suck" i.e. pull position, should i use a shroud for this? even though with or without shroud it will still be pulling air through the same surface area on the heater core, thanks!

I take it your setup is internal. If so, go with 4 fans in a push/pull shrouded setup.

...or, you could do something like I have. I have an external setup with a Comair Rotron Caravel (10" fan ) pulling through a dual heater core with a newegg.com box as a shroud. With the fan undervolted it is near silent, but still moves >150cfm I would say.

for my setup, i just got in the mail today from an auction i won off of eBay, 2 delta fans 120mm, and when at full blast the move 130CFM each, so ill probably prop them at half power, that'll more than enough i feal.

What I am doing is setting up a new external cooling box that will fit under my case.

I will post some pics when I am done, but this is what I have so far.

I took an old at case and mounted the core on the top of the case with shrouds and fans on each side. Then I laid it on its side and mounted the pump and resivor.
Then I cut off the excess space on the at case and remounted the bottom on the cut edge.
The top has fans, and the bottom is solid, as for the sides, I just used some blue filter material to keep the dust out, and actually it doen't look all that bad. at 35 cents a filter, they are cheap to replace too.

This whole system sits under my cpu case on its side. I don't have it completely put together, but like I said, Ill take some pics when I do.

Push/pull is slightly more effective than either push OR pull.

Pull (suck) is slightly better than push (blow).
Pulling air through the radiator has two advantages in my book:
fan blades inside and it reduces noise slightly.

Shrouds are perhaps the single most effective addition to ANY fan/radiator cooling system: they minimize the dead air space created by the fan hub(s) and effectively increase your cooling surface.

Shrouds should be used between any/every fan and the radiator as long as the space is available.
I personally have found that 1 shrouded fan pulling air through the radiator is better than 2 unshrouded fans in push/pull.
And it is quieter too.