Yeah, they'll bolt up. There's even a '74 455 that has a YR code, like one of the '67 360hp 400's.
Of course, if anybody looks at the casting number, date code, or cubic inch cast on the sides of the block, they'd see it wasn't a '67 400. But, I suppose you could grind all these numbers off, and/or make 'em un-readable. And, I assume you know that the 455's have 5 motor mount bolt holes, and the '67 engines had only 2.
Of course, I'm sure you know that you can just build a stroker using an original '67 400, or at least use a 400 block from another year, which has a code used on one of the 360hp '67 400's. That way the code and side numbers would look correct. And, if you run the '67 670 heads, you'll need dish pistons, for pump gas use. A '67 iron intake, and a '67-'68 Pontiac Q-jet, with a round tag, would help it LOOK more original. I suppose you could fool some people, who don't know much about Pontiacs.
http://www.wallaceracing.com/enginesearch4.htm