I am putting a vvti engine into a boat, and all the suppliers of marine exhaust manifolds can only tell me that they were designed for the non-vvti engines.
Do the vvti engines have the same port and stud pattern as the earlier non-vvti's ?
non-vvti headers are reported to be compatible with vvti engines. Both 1uz and 3uz. Check toyodiy.com, I recall even header gaskets share the same part number.