Engine Radiator help!

[Boogieman12]

I need some feedback please. I purchased my 92 fox about 8 months ago. Went into it knowing I wanted to build a new engine. Now I'm there. I have a new 363 on the way. Problem is the PO slapped a 94-95 5.0 in it with a procharger. Of course headgaskets were leaking. It has a pretty good Griffin radiator in it but its looking nasty and brown inside. What can I do to clean it out really good out of the car, so i dont get it in the new engine and not have to spend hundreds on another? Ive seen letting citric acid sit for a bit inside does wonders anyone have experience? Also any recommended electric fans that dont take up too much space? Running a 12 rib thanks

 

[billison]

Flush it like crazy till it’s clean ( tap water) then start flushing with distilled and any over the counter rad flush, run that a day or 2 then flush again till clean, then make sure it has the proper mix of coolant