The ONLY desirable feature of the 848 head is the smaller chamber volume (same reason as 235 on 261) - a small but cheap compression increase.
It's nowhere enough to get actual high compression (above perhaps 9.0:1), which requires decking the block, milling head or using a domed piston.
Clifford's halcyon days are long past.
They have an unfortunate tendency to, shall we say, use poetic license to describe the benefits of their products...
