Hi,

I have to install 2 set headers on my boat ( CMI) I want to know if would be better to change pressure regulators to have of better performance? Excuse my English

Which engines and which header model??

Best Regards,
Ray @ Raylar

Headers is CMI and engines 496 ho

Regulator change not needed for that 496HO CMI installation.
However make sure your fuel pressure under full load is between 43-45psi with the vacume line disconnected.
Be sure to service the filters in your Coolfuel fuel pump unit regulary to avoid restrictions that can cause the fuel flow and pressure to drop and damage the engine under load.

Best Regards,
Ray @ Raylar