Maybe TDC. You want it pretty retarded which is what Ma did back in the 70's in some cases to pass emissions. Keeps the nitrogen (nitrides?) of oxides (NOX) to an acceptable level. Not sure if subbing in a tamer cam would be something you'd want to do to get it to pass or if that would even be needed but you gotta do what you gotta do. At TDC it may need a milder cam to even run somewhat. Keep searching & here's a BTT for ya