400 rebuild or 290hp crate 350

[Zoomad75]

Originally Posted by Billla

I don't know of any stock-block 400's that aren't siamesed bores. They all have the same bore centers and bore...there's not enough room there for water all the way around. Source of your information?

Ditto on that! Where are you coming up with 509/400 blocks don't run siamesed bores? I've been around a few and read up on the subject and have never heard of a non-siamiesed bore 400. I can't imagine GM tooling up two separate castings for the same size engine The way I undersand it, there's no way to fit the 400's bore size in a conventional small block wrapper without eliminating something. In this case they dropped the water jacket between the bores to facilitate the large 400's bores while maintaining the same bore spacing as every other small block made.

I'm not sure how the giant World blocks get 427/454 CI out of thier small blocks but they aren't stock GM castings for sure.

I'm not trying to start a flame war I'd just like to know where the info is on non-siamesed bore 400's are.