I've had a look at the cam info, just not too sure what it all means. Duration especially. It seems some of the more 'normal' engines had similar, if mot greater lift/duration than the GT cam, which i thought was the best OEM item available (for hydro heads). Can you enlighten me further?

Its just the different design between the solid lifter and hydraulic heads which means the durations are different. Couldn't tell you why exactly though

No, but what does a greater duration give you, and what does a greater lift achieve?

No, but what does a greater duration give you, and what does a greater lift achieve?

Oh Duration is just how long the valve is open during the rotation of the cam. So a GK cam for example would have the inlet valve open for 229 degrees of the full 360 degrees.

The longer the duration of the valve being open, the more air can pass through it.

Valve lift is the same, the higher the valve lifts, the more air can pass by it.

Because the duration of the cam will affect the lobe shape, I'd imagine the solid lifter cams have a greater duration to stop the lobes whacking against the rocker arm, and create more of a 'pushing' motion rather than a 'thud'.

With hydraulic tappets there is a cushion of oil which will probably absorb the impact of the cam lobe, and therefore the lobe can be more aggressively shaped.

I could be wrong though

Right, simple as that. Then it's as i thought. Thanks for that. So the solid cams will have high durations as standard for the reasons you described above