Thermoquad jets

Have a look on the mounting feet for the model number. It will be 6xxx or 9xxx. You can then find the original specs for that model on line. If the rods you have are not correct for that model, pick the thinnest rods as a starting point.
1966 67/52/45
2005 65/55/40
1996 69/48/35 [ very rich power step ]
1998 70/57/40

Bear in mind that the engine is now 'modded', so original rods/jets are unlikely to be optimal, but a good starting point.

What has been done to the engine?