Rust inside engine block

[busmania]

My engine has 1000 miles or so on it and I took it out to address some things (not engine related) before getting my interior done. It seems as though the inside of the block is very rusty. I flushed the block and flushed and flushed and flushed and flushed and flushed some more before building it. In the 1000 miles I’ve probably drained the radiator for various reasons 3-4 times. Mostly running 50/50 antifreeze but I did run straight water for probably 3-400 of the miles as I was diagnosing an overheating issue.

Anyway, it seems as though the radiator fluid is dirtier than it should be for an engine of this age and I’m seeing a ton of rust in my radiator outlets. But, what really got me curious is the tube between the fuel pump that goes under the intake/breather. I sandblasted this and figured since it was in oil it didn’t need to be painted. BoyI must’ve been wrong. This thing is so rusty after 1000 miles. Thoughts?

Stats. 40 Ford, aluminum heads but with graphite gaskets. Aluminum radiator that I installed 500 miles ago (the new drake radiator caused overheating but even when I replaced the radiator before I went aluminum it seems the fluid was too dirty too fast).

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