455 and a 4 speed in a 1966 Special

It's really tight otherwise

 

Same on my 65. I didnt need to swap, But I didnt know about that either till now.

 

This is a 67 with a 455, headers not exhaust manifolds but here is the way I ran the brake lines.

 

Sorry forgot picture

 

The AC heater core on a 67 has the top tube angled toward the engine. The non-AC core has it straight. You can use the non-AC core on an AC car if you open up the top hole a little. Then the top hose should clear the big block head/valve cover.
https://www.v8buick.com/index.php?t...ore-1967-special-with-ac.352573/#post-3022806

Cores are available at Summit.