Good job!

But welcome to the world of the 55 motor and the heat soak that comes with it.

We have cars with over 600wtq that just barely run 10's (mine included) We have massive cooling systems including rear mount tanks/dual mez pumps/ etc. The front HE no matter how large just won't get it done.

Do you monitor the car at all? If so, check your iat's under load. It will surprise you. I bet your timing is going haywire...