G’day D’man,
A few observations:
Replacing head bolts with studs will make it difficult to install (and remove) the head.
I’d suggest looking to longer bolts or a thread repair solution.
If going with longer bolts, be sure there’s some extra room at the bottom of the hole. You don’t want the bolt to bottom out in the hole while you’re torquing it down.
Also, there appears to be a hollow locating dowel near the water pump end but none on the middle bolt hole as is usual.
Measure the head thickness to be sure if it’s serviceable, but it looks OK.
As JB points out, the 821 cam (or any wedge head based cam) won’t work in a cross-flow.
Here in Oz, we got the same version of the R17TS as they did in Europe rated variously at 120 or 125HP - brochure HP. This was the 844 engine of 1605cc & 10.25 compression using EFI.
Valve sizes in those are 42.1 inlet and 35.35 exhaust using different valve springs, con-rods etc.
Cam timing was 40/72/72/40.
I only mention this because it’s a tried and true base configuration for reasonable power without worrying about exotic fuels etc.
I can’t see the piston crowns properly, but do they have a slight dome?
What is the bore diameter?
What car did this engine come from originally?
There’s obviously some coolant circulation differences.
I don’t know for sure but cross-flow heads using a water pump located at the timing chain end also have some slightly different coolant passages as well. It’s possible the intended coolant flow is reversed . . or perhaps straight through from one end of the head to the other? . . dunno.
It’s not insurmountable, but that needs to be figured out.
Probably an electric water pump could sort it.