finally have them both side by side, and i was able to take a closer look at what makes the PDE/euro-r head different from a "stock" one.
the only significant difference is that the euro-r head has enlarged/ported intake runners, it comes that way from the factory. the euro-r intake manifold has runners to match. so that makes me wonder if anybody else has noticed this, because many people have installed euro-r intake manifolds on stock p13 heads
internally, the heads appear to be completely identical. they share the same rocker arms, cam caps, etc. judging by the valve seat machine marks (the ones from original casting of the head), it appears that they have identical valve angles as well (some have said valve angles were changed from 60° to 75° or whatever). of course i didnt get a clear measurement, but its way too similar to be any different.
other than that, all of the other studs, bolts, and holes are in the same spots.
PICTURES:
unfortunately i do not have a completely stock P13 to compare the PDE one to, but the P13 head i have has ported intake runners, and you can clearly see that the PDE (unmodified) head's runners are the same size.
PDE/Euro-R runners:
P13/stock Ported runners:
approximated valve angle comparison (P13 left, PDE right)
- angle is compared by distance from cam journal. the distances match for all valves on both heads
intake side comparison (PDE top, P13 bottom)
exhaust side comparison (PDE top, P13 bottom)
timing belt side comparison (PDE left, P13 right)
tranny side comparison (P13 left, PDE right)
valve/gasket side comparison (PDE top, P13 bottom)
rocker/cam side comparison (PDE top, P13 bottom)
