Shoebox radiator/cooling airflow questions

I have a 49' Shoe with 239 flattie .030 over, Offy heads, 4 barrel carb with Griffin radiator with 6 blade crank driven fan and Bubba dizzy with stock water pumps with about 30% glycol 70% water. Temps are fine (one side 175ish, the other 185 ish as verified by IR gun) when going down the road at 70mph or in traffic when ambient temp is around 70, when it's cooler she runs cooler yet. I am running stats. Once the temps get around 80 or above she gets drastically warmer, up to 210ish. I do not have a shroud on the radiator which I know is not helping, the fan is about .75-1" from the core but does not have full coverage, the upper and lower corners of the rad are pretty much void of the fan pulling any air through. I'm thinking with the hotter air/lack of shroud the system just isn't efficient enough to remove all the heat once the temp gets warmer? I shot parts of the system (heads, hoses, radiator tanks/tubes) with an IR gun and found nothing that tells me there is a obstruction anywhere in the system. I flushed the radiator just for shits and not much Santorum came out. I remember seeing another thread and somebody mentioned that there are several pieces that should be on a Shoe to direct air through the radiator, I saw some seals and shit for the radiator and hood on Dennis Carpenter's site and was wondering if these additions would change how my Shoe cools, as far as I can tell they are not present on my car. Anybody out there in Shoebox land care to lend me some suggestions? I'm sure some Skip Haney pumps wouldn't hurt but I'm willing to try the simplier (read: cheaper or free) things first! Thanks in advance for any answers.

 

Without a fan shroud there is no guarantee that the fan is actually pulling air as it is entirely possible that it is just churning the air (in a circular motion)

Yes you need a shroud all most as much as the air dams that direct air thru the radiator . Ford put them there for a reason and the reason wasn't for dead weight. Without the air dams you are loosing much potential air flow thru the rad.

Also, depending on your rear gear ratio, you may see a dramatic drop in temps if on hot days you stop spinning the engine so fast (slow down a few mph).

With my stump pulling 49 Merc 1/2 ton I am limited to about 65 on a hot day but when the sun goes down I can easily pick up another 10 mph.
For me, Normal temps of 200 to 210 = 65mph on a hot day. When the sun goes down the temps will drop to 160 or 170. -It's that dramatic.
Then again the 1/2 ton rear ratio is geared for the roads of the day (1949) so to be honest It would be more appropriate to run this truck at 45 which would have been the speed limit on the best of the best roads in 1949. It's all relative.


My 39 1/2 ton has a much taller gear ratio being based on the car rearend and it will run all day any day at 75 and never get past 185. If I push that all original truck to 90 the temps will climb just as they do with the much lower geared Merc. Gear ratios really make a difference.


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