Engine painting

I painted my block in the car, when the oil pan and timing covers were off, but heads and exhaust manifold on. I used Rust Destroyer in rattle can ($11 Home Depot). It primes bare metal and is good to 800 F. I cleaned and wire-brushed the block, but still some original paint and hard rust. I similarly painted the heads on the car when the intake was off. I'll touch up someday if I ever remove the exhausts.