Engine Fitting and Cooling Question

Firstly I want to say kudos to the Automation team for the latest update! Fitting the engine to the car body is one of the features that I'm waiting for (besides v6
).
But I have a question. Especially about cooling. I can't fit an engine because the car body can't cool specified amount of HP. I know that I need to add some cooling fixtures to do so, the problem is not all grilles and vents add the cooling capacity. Is this a bug or just haven't been coded yet? What are my options besides of adding grilles and vents? I'm fitting a 400 HP engine and I already added so much vents and grilles that my car looks stupid but I haven't reached cooling capacity for 400 HP engine.
Second question, how do I enlarge the engine bay? I wanted to fit a 6.5 L engine but I can't.
Thanks in advanced guys!

But I have a question. Especially about cooling. I can't fit an engine because the car body can't cool specified amount of HP. I know that I need to add some cooling fixtures to do so, the problem is not all grilles and vents add the cooling capacity. Is this a bug or just haven't been coded yet? What are my options besides of adding grilles and vents? I'm fitting a 400 HP engine and I already added so much vents and grilles that my car looks stupid but I haven't reached cooling capacity for 400 HP engine.
Second question, how do I enlarge the engine bay? I wanted to fit a 6.5 L engine but I can't.
Thanks in advanced guys!