400 Ford w/ Aussie Cleveland heads
The only "advice" is that there are not a lot of 400 pistons. Most people that are building a performance 400 bush the rods and use 351C pistons. The 400 stuff usually ends up way too far down in the hole to get decent quench - an therefore is more prone to detonation. YMMV - work with your shop on this issue.
1967 Falcon 4 door 351C - 70 Mustang 351C
Owner built, owner abused.