Here's a Tech Article on the various ways to convert from four-lug to five-lug:
Pelican Technical Article: 914 Five Bolt Pattern Conversion Guide
The short version is that there are three main ways to do the front:
- Re-drill the hubs with the five-lug pattern. You have to re-do this every time you replace the front rotors, since the rotor is part of the front hub.
- Use bolt-on four-to-five adapters. I personally dislike this approach, as I do not feel the common adapters are good enough to be safe on a 914 that is driven the way it was meant to be driven.
- Change over to a 911 front suspension.
The 911 struts bolt onto the 914 A-arms. You get big brakes and five-lug hubs at the same time, which is nice. You can use the 911 A-arms if you like, but you will have to use the torsion bars (and the eccentric at the back of the torsion bar) from the 911 as well because they have a different number of splines.
The rears are a bit more complex to do; you basically have to re-drill the four-lug hubs. Best to have studs pressed in, because the studs can actually provide more support than a threaded hole through the thin material of the hub. (There are specific combinations of parts from various year 911s and 944s that actually let you use hubs that are already five-lug, but those parts are relatively rare. And the 914-6 hubs are even moreso.)
--DD