I remember reading a thread or 2 about installing the gen3 sump on a gen2 engine. I have all the parts needed for this now so I'm hoping to do this. I wanted to re-read the past thread that described this upgrade but still after so many searches I cannot find anything. 
I just want to make sure I'm going to do it fine.
This is my understanding so far.
Needed:

• Gen3 2 part sump with oil pick up and windage tray. Gen3 oil pump. Gen3 oil cooler or remote oil cooler set up.

Things to do:

• The gen3 sump need 2 holes drilled in it for the gen2 alignment thread, and a gen2 bolt hole.
• These 2 alignment threads also need to be removed and replaced with longer threads or use bolts.
• Longer bolts will need to be used to install the sump as the alloy sump is thicker.
• Gen2 rear seal housing will need new holes drilled and tapped to match sump
• The alloy sump needs 2 cut outs to clear arp main studs.
• There are 2 extra holes in the gen3 alloy sump that are not on the gen2 block, does the block need to be drilled and threaded for these 2 extra bolts or will the sump hold and seal fine without them? I don't see the need for this but I would like your inputs.

Any inputs are welcome and if anyone does have links to previously completed upgrades please share.

you'd also need to drill/tap holes to attach the windage tray. 2 are there for the pickup, but there's 4 others.
 
i'm going through this process at the moment, but it's fitting to a 5s block (one without balance gear)

I'm probably going to drill the extra hole.

Can I ask why?
I'd like to understand :)

Mine is on a 5S block. I went with drilling and taping the holes, as its not hard to do.
The alloy section dose need to be ground to fit over the ARP studs. Ill have a look to see if I have any pics but dont think I took any.

Thanks for the pics, I just thought it's so close to the other hole it probably isn't needed. I forgot all about the windage tray holes so I might as well do the extra sump holes at the same time. 
 
Gatesys, I've had a gen3 sump and pump laying around for a while, and with the new engine I'm building I like the feature of the oil filter down the bottom. I had to go buy a windage tray new though. Also I think the gen3 setup looks a lot stronger and neater. I already have a remote oil cooler and I guess if I wanted to I would be able to run 2 oil filters if I felt like it. Probably not needed.
 

use one for the oil filter and the other for the cooler.

Got run down with assignments, but had a good crack at this today.
I have found with the alloy sump bolted on, the rear of it hangs with about a 1mm lip past the end of the block.
Has any one else found this? I can get a pick if needed. 
For the gearbox to bolt on flush I will have to get the rear of the sump machined to sit flush with the rear of the block.
Or have I missed something?
Thanks again

Dont forget the piece of metal that fits between the block and gearbox.

All holes are drilled, and crank and pistons are in, now I need to get some seals and gaskets. And determine what size HG to get.
For this sump, do I need to buy a gen 3 dipstick and tube?
and the rear plate between the block and gearbox, the gen2 one is the same thickness as the gen3 right? 
Thanks