JMortensen

Agree. 8.8 IRS is easier than stick axle swap. FWIW, 9" isn't that great as they came on production cars and if you went that route you'd need all custom stuff. You'd have to replace the housing to take that much power and housing will be too wide, etc. Can buy the whole thing upgraded and built to fit, but the pinion is really low, which is another issue. I'd rather go custom 8.8 solid axle if you're going to a solid axle. Almost as strong, cheaper, just as many gear options, better pinion angle, etc. If you want REALLY strong, Dana 60.

You mean the right way. Nicely done.

I climbed all over mine when it was on the rotisserie, just be careful, it is possible to tip it. Most surreal part of working on mine was with car upside down sitting on the top of the windshield opening with my legs hanging out the front and welding rust on the cowl/firewall junction with my head right about where the pedals would be.

Shim stock that is .004" is super easy to cut. I made shims for my LSD and cut them with scissors. You might consider buying a piece of shim stock and cutting a shim out if the alternative is paying a machinist to turn a new spacer on a lathe. Once it's in there the shim is not going to move, and when you're torquing the nut you can prevent the stub axle from spinning, so you won't screw up the shim while tightening. Looks like $11.30 from mcmaster.com: https://www.mcmaster.com/9011K815

Check the seal. If you don't drive it all the way in the lip on the seal hits the axle. Other than that shouldn't be much to it. If you had to make a new spacer the thing to do would be to test fit without the seal until you get the right endplay (almost none, but there is a spec for it) then install the seal and torque the shit out of it. Also there is a bit about torquing until you get the right amount of drag, but they're ball bearings, so the drag really shouldn't change with the torque. I always red loctite and then put the impact on 5 and give it lots of ugga duggas and have never had any trouble. I think the FSM is just wrong on that torque to drag thing. Doesn't make any sense.

Duh. I had never thought about it, but the countershaft is under the mainshaft, so yeah, turning it sideways or flipping it is the answer. I remember the Porsche guys flipping transmissions for 914 swaps I want to say, but it was 25 years ago and I don't remember what all was needed. Sounds like a shift linkage nightmare on a T56, but your T10 and Jericos have external shifters, seems like it would be a lot easier to do on one of those.

I was thinking about the trans being the low part, as I had issues with that too (trying to keep it from hanging below the frame rails. My though was whether it might be possible to raise the tail of the transmission and then lower the front of the diff to keep the angles parallel. Haven't looked at it, but was just thinking about this the other day, probably after looking at this thread. Without some way to get clearance for the trans, I'm not sure how much lower you can take the engine.

Double checked the compression bit, would be 10.4 with 706 heads (unshaved) and 9.9 with 799 heads. It's enough of a difference that you can see it in Holdener's videos.

Are you going to dry sump it, or band aid the stock oiling system like I did? I'm running a Holley oil pan with Improved Racing baffles and IR thermostat remote oil cooler adapter to a cooler and 3 qt Accusump. Dry sump is the better way. BTW it's been a while since I looked into it but one thing that I was interested in but didn't end up doing was to make a baffle that bolted onto the main caps and directed the oil back to the pan. Basically just need a wall that doesn't allow oil draining back to flow directly onto the crank. Also if you plan on changing the oil pump, watch some youtube videos on how to do it right. You can't just slap it on there. I think I did the barely snug the bolts and then spin the motor a couple times method, but you can also check clearances with feeler gauges IIRC. You'll laugh at how easy the cam swap is. If you're working the heads over, might try to find some 706 truck heads. They're readily available and the L33 has the larger chamber 799 head which lowers compression. The truck head is actually the better choice for a 5.3, think it puts compression at mid 10s, where the 799 is 9.9 IIRC, but double check my numbers. Richard Holdener's youtube channel has a bunch on comparing heads, if you're interested. You can buy them CNC ported pretty cheaply too. Just amazing how cheap stuff is for a GM V8, and how big the gains are, especially in the trucks with their tiny cams. Good cam will get you 100 hp easy. Might look into the LS7 style lifter upgrade and a rocker arm upgrade too. I will eventually get to those on mine. The thought of losing all the needle bearings on the stock rockers has me a bit concerned. I think one of the main issues with road racing these engines is that they pump too much oil to the head. I ended up putting restrictor pushrods in to slow down the flow of oil to the top of the engine, and I think that was a good call, might look into that.

Never done a flow test, but thought I'd chime in to say that my square port header, purchased from Arizona Z Car in the 90s but same header, had the tubes formed to meet the port shape incredibly poorly, and the inside of the primary was pinched down enough that I actually felt the need to port the header a bit on a couple cylinders to try and open them up before installing it. I'm sure a round port header wouldn't have that problem. I was still pretty green back then, I think today I'd probably beat the tubes or maybe use two prybars in the primaries to spread the tubing back open again and then grind and weld if necessary. I just remember being very unhappy with it.

Mark sent a picture. Looks like they were using a borescope. Said it happened a different time and sheared all of the teeth off, sounds more like Ben's failure.

This looks amazingly similar to Mark Haag's drive gear failure, which he noticed at idle IIRC, so he also didn't destroy his engine. Messaged him to see if he still has the pic or wants to jump in on the thread.

I wish I had the creativity to make 3d parts. My only experience was when Austin Hoke 3d printed a caliper bracket and sent it to me, then I was able to bolt it on and make sure it fit. Was great for that.

Z's taking flight is not something I worry about, but also the last time my Z was on a road course was 2002 and it probably topped out at 120ish with the triples and the L28. Many people more worth of the title "racer" than me. Unfortunately I spent way too much time building and way too little time driving, and it's been all autox for the last 20 years. Hopefully I'll fix the shop/driving ratio in the next couple years.

Sealing everything up tight would be the goal, but in practice I don't think you're going to see a whole hell of a lot of difference one way or the other. I'd put a piece of sheet across the opening and fasten to the fender or bucket, and then cut the hole in the middle for the scoop. Sometimes I do these "simple" things and then hours into it I realize that it was a waste of time, then I have to do the sunk cost fallacy appraisal and decide to finish or cut my losses. Your mileage probably won't vary too much. ;)