The 130hp engine can be built on a relative budget, the 170hp engine on the other hand will require a few more uprated parts.

Crank/Rods.
The standard crank & rods can be retained, but for piece of mind it maybe worth having the rods stress relieved, & everything nicely balanced up. Adding a set of ARP rod bolts gives peace of mind.

Head.
The cylinder head will need to be of a higher spec. The 29mm exhaust and 36mm inlet valves can be retained, but it may be beneficial to go to a bigger 30 or 31mm exhaust valve. Obviously the head must be ported to suit. The sodium valves do not need to be retained & can be replaced with high quality stainless items if needed.
The standard Payen BK450 head gasket should be used, or a high quality steel shim item. ARP head studs, & drilling for 11 studs is recommended.

Pistons/Block.
A centre main strap should be added. A high quality cast piston could be used, or a high spec forged item.

Cam.
Suggestions - Piper Phase 2, this is where this cam really comes into its own !!

Timing Gear- Add a duplex timing chain. A vernier adjustable item can be used or use offset keys with the "fixed" type to time the cam in accurately. Or a belt drive is fine.

Clutch/Flywheel.
Steel flywheel & backplate. I found the Grey diaphragm & the AP rally/race plate to be on the limit at this kind of spec, so had to upgrade to a double grey while retaining the AP plate.

Gearbox.
A twin pin diff, straight cut drop gears & a full SC box.

More boost.
A decent intercooler is essential at this stage, you'll need to run about 15-17psi.
The compression ratio should be about 8.2-1.

Others.
Use a high capacity oil pump, high grade cam followers, good quality main & big end shells etc

Obviously this is only a rough guide, but with a correctly built engine you should see around the 170hp mark.