340 valvetrain help

Hi guys, I am new here. Just picked up a 340 Duster and have been going through it. When I drive it I get quite a bit of knocking noise around 1500 to 2500rpm.
I took the valve covers off and it has nice shaft roller rockers.
I am not sure what cam is in this engine, what type of lifters or anything.
Checked the timing and it was at 25 degrees initial and around 42 total. Sounded kind of high to me so I retarded it some.
Any help or a point in the right direction would be really appreciated. Here is a photo of the new ride.
AndrewView attachment photo.jpg