Jano do your lifters have a roller tip too?

Another problem is where the oil comes from, lots of engine (these too i believe) pic up the oil feed for the head from the centre main, a better design is to take the oil feed for the head just after the oil filter....

Even then oil filters only filter to 10 microns (ish), this is more than okay for bearings as the 'gap' between a bearing and journal is large enough to avoid any damage.... problem with cam lobes is that there is obviously no gap and massive wear can occur even with metallic particles smaller than 10 microns as we have seen. I have seen some heads with magnetic pic ups after the oil galleries (mostly agricultural) as most of the damaging particulate in the oil is ferrous.

Another massive problem with kent/piper etc is that their surface treatments are near to nill, especially compared to an oem camshaft of good quality.

Canada1 have you done any flow testing of inlet manifolds btw?

Rob,