Yes, I am currently using the HK450 head. Works great. I didn't try to make their swashplate fit, because it didn't look like it was a good match for the frame, so I didn't even bother. I am still using the stock swash. I did notice though that the Exceed Genesis 450 V2 from XHeli has a replacement cnc swashplate that looks like it would fit the Axe 400. I haven't personally tried it, so I can't really comment on it, but it's only 13 bucks, so it might be worth a try. Here's the link

Hope this helps!