Rule of thumb, hot running at speed means radiator. Hot slow means airflow.
It sounds like you are hot running slow. Not enough airflow.
I think that car wants a radiator shroud. Most do.
Also, check pulley sizes... is there an aftermarket "underdrive" pulley installed?
It runs hot all the time.It overheats at idle and it overheats while cruising; at 60mph with 3.54 gears, the temps climb to 200 (even on a 77 degree evening). Then as I slow down to about 40 they climb to 210. As I slow down to turn into my development (20-25mph) they continue climbing to 220-230.
Here's a question for you. Do you have a six or eight blade water pump impeller?
I recently talked to Bob at Glen-ray about this. He said your pulley ratio determines the number of water pump blades you need. I should have wrote down the measurements but didn't. Anyway, I'd measure your pulleys and find out what type of water pump you have and then call Bob -> (715) 842-3352
Bob knows Mopar cooling systems and will be able to offer some advice.
Also, as I recall,
small block radiators have a smaller lower inlet which would probably be the crux of the matter. You likely need a big block radiator.
Years ago we tried running a freshly cored 26" small block A/C radiator with a mildly built 383. It would run on the warm side. It's that lower inlet that makes a difference I guess.
