And the magnum timing was advanced to 56* it was as far as I remember the only small cam that was ADVANCED that far not retarded.
All Cummins form day one: Direct Quite from Service Manual.
**Advanced timing means the fuel is injected earlier into the cylinder during the compression stroke,
Retarded timing means the fuel injection occurs closer to TDC in the cylinder.
**The amount of push rod travel determines the time of fuel injection in relation to the piston position. The higher the numerical value of the push rod travel remaining indicates a greater degree of
retarded or slow timing.
The lower the numerical value of the push rod travel remaining indicates a greater degree of
fast timing.
** Injection timing changes are accomplished by advancing or
retarding the cam follower action to the piston position.
This is accomplished by changing the orientation of the camshaft lobe to the cam follower using different camshaft gear keys. (
emphasis Cummins)
Note: Advanced = moving cam follower (roller) towards the inside of the engine.
Retarded = moving cam follower (roller) away from the inside of the engine. Adding or removing follower box gaskets or using offset keys, or combination gasket/keys.
All Cummins C,J,H, NH, NTs, BC1,2,3,4 Vs, Ks use 19degree BTDC, position of injector plunger 0.2035"
Cummins JUNK put beans of the table for 10 of thousands of truckers.
petepilot. SC high Hp camshafts, all numbers originating from >
143450,3023229, 3023177,152960, 3023229, 3608842
Just had a customer call about some problems with a big cam 290 in a 1979 Kenworth . 
