I had thought of this too.
Outside of idling, due to the design of the core support, isn't it likely that the heat shed from the coolers, if they are anywhere in the core support , is going to still go through the radiator? I don't know what the airflow looks like, but I suppose that only a small portion of what "hits" the front of the truck can make it through those small openings for the radiator, the rest of it has to simply be shoved out and around the vehicle.
Cheap and easy "fix" to move them and at this point, I think anything is worth trying.
I had read that the lower "spoiler" (that only came on 1/2 ton trucks apparently) will help to get air through the radiator at speed due to the low pressure it will create in the engine bay. Not sure I completely believe that, as you'd think 1/2 tons would need that far less than 3/4 and 1 tons, but just something I read.
In the future (I've got all the parts already) I plan on logging oil temperature, as well as trying to determine the efficiency of the oil cooler based on the oil temp.
Darren, do you see drops in your oil pressure, or do they stay pretty constant? In watching mine, even as ambient temp increased significantly, if load on the engine stayed the same, oil pressure reading stayed very consistent. Kind of going off track here, but it is likely that the oil cooler is dumping a lot of heat. Even with that, the new radiator (along with everything else you've done) should have made changes IMO, which it doesn't sound like it did.
As to the mount question, the Champion radiator my Dad got didn't fit the big block radiator support, the Champion was a bit short. IIRC, the big block radiator actually ended up being a 1/2-1" taller than the small block. He made some spacers out of sheetmetal to make up the gap at the top mount. Is your problem that the mounting surface on the radiator itself (the "flange" where the rubber mounts are supposed to sit) is wider on the aftermarket radiator, not the height?
