Turning torque for engine

You may have more room than you think. I had something like 3-1/4" from the water pump snout to the back of my Champion radiator on the avatar. I wasn't sure what I was going to do given such a small amount of space. One thing in your favor is the water pump snout does not fit up against the fan motors - it actually tucks in between them. I was skeptical until I made mine up per the pic I shared earlier (note that I blocked the areas that look to be open along the outer edges as part of the final build).

And again, this is not about heat rejection at max load. This is about part throttle heat rejection so you should have plenty of cooling capacity in that radiator. Again, the avatar's 408 is kept in check down here in Florida so far in 90+ weather. It may get up as high as 195 (usually if I forget to flip the 2nd fan on) but typically runs in the 170-180 range.