Run electric fans all the time?

Thanks. That is also my current diagnosis :)

Aren't there only two ratios for the B/RB, either 0.95 or 1.30? Anyhow I'm going to try the high flow pump and see how THAT goes.

How big an engine are you successfully cooling with the Contour fans?

The B/RB ratio was .95:1 or 1.4:1 with AC. The .95:1 was with a high flow 4.38 " diameter 8 blade pump the 1.4:1 was with a 3.5" diameter 6 blade pump. That reflects what the factory did as far as managing the overdriven fan and pump with the water pump output, all of the V8's got an 8 bladed pump with the non-AC set up. With a 1:1 ratio you need the 8 bladed pump for best cooling, the 6 blade pumps were for the overdriven pulleys.

water-pump-info-all-mopars-jpg-jpg-jpg.jpg

My engine is a 340, but it's .060" over with iron heads. HP is probably in the 420-430 hp range, I've never dyno'd it though so who knows.

It also has A/C and this absolutely ridiculous engine bay where the exhaust manifold basically touches one of the fan motors:
View attachment 1715593727

Yeah between the almost complete lack of a grille opening and the ridiculously tight engine bay I don't know how they kept those things cool. That picture doesn't even really do justice to how little room there is, when I went to pull the fans from a car at the yard I was amazed how tight it was. I pulled a lot of stuff just to get that fan shroud out, radiator included. It was dumb.

It also doesn't convey the hp per cube, that was a 2.5L V6 that made 200 hp. That's 1.3 hp per cube, and that's an important factor too. My 340 is less than that per cube, although I think goldduster318's is higher.