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. 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. 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.