
Looks to be reasonable quality, comes with ARP fasteners and no less than three different plastic alignment tools. The plate closest to the flywheel has a proper marcel spring, the other one doesn't (or is very minimal). Need to pull finger and sort out the master cylinder then get this changed over.
In the mean time I finally bought a proper alternator to resolve some low voltage issues. I had a new 120A unit but it was one of those universal ones so it didn't put out a lot at low revs. I was using an old VN 85A one for a while which was marginally better but still not great. Pulley ratio is fine (~2.45:1) and engine idle speed is now relatively high (925rpm) which gives me a good 2200rpm at the alternator at idle. However I have aftermarket injectors, two fuel pumps, twin 14" cooling fans and by the time all that is going and you turn the lights on, the ECU was showing under 12V at times!
Solution: 140A Mitsubishi style unit as fitted to LS1 Commodores. This is meant to give better output at low revs and even came with a test report - 101A output at 2000rpm. Physically fitting it requires changing the pulley (I had to make a spacer but I do have oddball pulley spacing) and changing the tensioner bracket - if I ever get around to it I might change this to a turnbuckle type thing for easier adjustment but it works for now:

Wiring it up is the same as a VN unit, load and sense wires, but with a different plug or you can cheat and use spade terminals.
Speaking of wiring I thought I'd better replace the old starter, earth and alternator leads with new ones of appropriate size to make sure there are no problems in that department. Only problem is the leads come in weird colours:

Fixed:

Now the ECU reports an immediate 13.7V at idle, which doesn't seem to drop no matter what's running. Voltage at the battery/sense wire is a constant 14.3V.