Still working on finding a machine shop to bore out the block.
I did spend a couple hours finally swapping out the lower shock bushing, which I found was wore out when I put on new shocks.
After unbolting the shock and strapping it out of the way and moving the cv axle, I used my ball joint press w a 15/16" impact socket to push the old bushing out:
Old vs new:
New one pressed in:
Took it out for a test ride/get some groceries and...still have some banging happening when the suspension moves, so something else is still wrong. I'll replace the bump stops/jounces as they are also pretty worn, using the nicer looking ones from the parts truck and see if that helps, and recheck ball joints/sway bar/a-arm bushings...
To follow up on yesterdays valve lapping, I had bought this tool (crappy pic, it's OEM Tools large valve lapping tool). Simply put, it sucks. The "rubber" tips are anything but, they feel more like soft, flexible plastic instead. With moisture, either end would barely do a 1/2 rotation of the valve before coming off.
I did spend the time (should have done this first) to find the similar tools I knew I had, just didn't know where they were resting. I found 3, that are all at least 20 years, and probably more than 40+ years old, and all of them had softer, actual rubber suction cups, that gripped and stayed on the valves like they are supposed to...
Also spent a bunch of time figuring out what pistons to buy, from what I can tell from going on various auto parts sites, there are:
GM 89017849 (actually I would want 89017850, which are .5mm oversize)
These are all the same cast pistons, w floating wrist pins, dished heads, and opposing valve relief cutouts. Once I get the machine shop nailed down, I'll order the pistons from whoever has stock.
I'm sure there are other pistons that will work, but I'm going for a stock setup, with minimal risk and cost. There are forged pistons for way more, and maybe some other LS pistons will work, but I don't know enough about them to select them.
And a special shoutout to the ebay douches with the somewhat vague ebay lists for Mahle pistons for stupid money. They just have the p/n and charge 4.5x the price everyone charges for a single piston, but way less than what others sell a set of 8 for, and I know it's going to be just a single piston, w a return hassle...
Finally, a couple days ago, I ordered the Eonon Q80Pro head unit, w free backup camera and bluetooth obdii code reader, and the head unit came in (the other two bits actually shipped earlier, but from the other side of the country, so they will get here in about a week. I had planned on buying a similar setup to what I added to my '04 Sierra mainly to add Carplay support (an Alpine ILX-W650 HU, Pioneer NC-BD6 camera and PAC-Audio RP3-GM11 harness), but even with the xmas/boxing day sale discounts, this is about 60% of the price ($400 vs $500 for the Alpine, + $100+ for hte camera and $100+ for the right harness for my truck), and it includes the right harness for the truck, so it just plugs in.
Main HU, only about 2.5" deep so no problem with being too deep (way back the original radio I got for the '04 Sierra was a Pioneer AVH4000NEX, which needed a dash support cut out at the rear for it to fit in all the way).
The main thing with installation is figuring out this rats nest of wiring:
It's basically a bunch of plugs that go into the radio and the trucks wiring harness's. The manual has a single diagram to show how it all connects up, I expect it to be pretty straightforward, particularly since I've done this kind of thing before, but it may be a bit puzzling for someone who hasn't. However, I expect newbies will find it easier than the more traditional method, like what I did with my '04 (buying a head unit and a separate harness adapter, and having to wire the harness adapter to the radio yourself), and particularly if you try going cheap and just buy the head unit and then cut up the trucks harness to wire the HU up directly to that.
Edit: Misrememered the price for the unit, it was only $340 + 5% GST, not $400...