There’s a puffing sound coming from the side of the engine so we assumed it was manifold gaskets so we changed them and it didn’t affect the sound at all. What else could it be coming from?

 

Do you have SAI (secondary air injection) on your Dll? There will be external tubes above exhaust manifold, if you do. They could be cracked, common issue. Also check all of the tubes and hoses on the system for leakage. If you don't have SAI or tubes/system seems okay...could be cracked exhaust manifold or head gasket leaking externally. Normally, a cracked exhaust manifold will quiet down some as engine reaches operating temps, while head gasket leak will be opposite.