Not trying to sell truetracs but am curious why would one choose a detroit locker/grizzly locker over a truetrac.  I think of the lockers as more for dedicated offroad/rock climbing.

You'll never know a truetrac is there (no noise, no weird tire wear, no unlock scenarios), it will last longer than most trucks, and in the odd chance one tire has zero traction you can make your tire that has traction spin by feathering the parking brake...I've done that.

Jay has a good reply regarding Detroit Locker differentials. And his mention of the overblown reputation concerning Detroit Lockers and online lore is spot on... WAAAAY overblown concerning the negatives of a Detroit Locker as compared to the hundreds of thousands of miles driven using a Detroit Locker I have experienced.

I fully believe part of the overblown lore stems from many vehicle owners not being well versed in how to actually build and modify chassis and suspension parts properly so they result in various inequities they built into their off roader, hot rod, collector car, or whatever via poor design and application and mechanical work and then blame the Detroit Locker for the weird driving results.

In my post I did state the various things associated with using a Detroit locker, both from a toy vehicle use, and daily drive vehicle point of view, because I want to be as honest as I can be when making recommendations. What I did not post are some of the real life issues I have witnessed when people complain about how poorly a Detroit Locker drive... Perspective is everything here and this is something you don't get with the vast majority of online reviews, posts and comments, regardless of the literal content.

For instance, a guy I know will strongly advise against running a Detroit Locker based on his direct experience. His experience is real, but perspective matters.
What you don't know is his direct experience, while real, comes from the perspective of a 1966 Chevelle running a home built 4-link rear suspension, a 600+HP big block, a 4spd manual... and running wrinkle wall drag slicks on the street, because this was his street race toy back in the late 1980's early 1990's. That car was really fast, and it was a handful to drive on the street too.

Another guy I knew had a K20 Blazer with Detroit Lockers in the front and rear differentials, and he bitched constantly about how horribly that thing drove because of the Detroit Lockers.
What most people never knew was that K20 was running 44" tall TSL Swamper tires, using a really high lift kit, and a bunch of cheaply done modifications to get it all to fit, all coupled to a 500 HP engine and mainly used for off road screwing around... But it was licensed and insured for the road so he drove it on the road even though he should not have.

My point... when reading the reviews about Detroit Lockers you really need to understand the perspective of the writer of the review because often, they are driving a poorly executed vehicle that would have driven terrible no matter what differential was installed.

The rear tires will wear differently than a vehicle with an open differential, but that does not mean they wear out super quick. I'm still getting 50,000+ miles out of my tires when using a Detroit Locker... Unless of course the tires are very soft compound. But normal road tires last a long time without issue (I do maintain proper inflation pressures and rotate tires regularly and this has proven to maximize tire life and use over the tires treadwear range) But they do wear differently than a vehicle not using a Detroit Locker differential.

The differential does make some noise, but once you know the noise is normal it merely becomes part of the operation of a Detroit Locker with little clicks and pops here and there... It lets you know it is still working while not being intrusive.
The locker does give rise to some driving differences, most notably when traversing long, sweeping curves, but this too becomes just part of normal driving with a locker and before too long the actions are just normal routine.

The HUGE plus of a Detroit Locker is the set it and forget it aspect.
Of all the various differentials I have driven over the years NONE of them are as durable, or as consistent, as a Detroit Locker.

Install a Detroit Locker correctly, and do the required lube change maintenance, and the next time you need to mess with it will be when the carrier bearings need replacement, or you literally break the differential in some manner through hard abuse.

The Eaton True-Trac is a good Torsen style differential, and it does work well. But it is not as consistently positive, or durable, as a Detroit Locker differential.

Bob, years ago I fiddled around with various lockers in my 10.25" Sterling differential in my 1990 F250, (7.3LIDI diesel)
From the factory it had 3.55:1 gears with an open style differential and the short style pinion, and about 60,000 miles on the whole thing.
I needed both wheel traction for MN winter driving.

I tried using one of the Powertrax Lock-Right lockers (lunchbox lockers) and it installed really nice, but the first one did not work properly. I was basically a full spool.
Summit was great with the return and sent me another whole unit to try after some discussion proving to them I'm not an idiot and I did not screw things up during installation.

2nd Powertrax, same easy install, but by this time I had researched quite a lot about these things and knew more concerning various clearances.
I installed the 2nd unit only to find incorrect clearances. Everything fit and installed, but things were too tight... but I had all the new parts from the 1st unit too so I started measuring, swapping, fitting, and doing what I could to install this thing to "perfect" specs per the manufacturer.

Installed, measured, verified... driven... still a spool with no differential action under any conditions.
After much trial and error, I was eventually on the phone with one of the engineers at Powertrax.
We spoke about my issues, he agreed I was doing things correctly and saw a video I sent to him regarding clearances and such.
Finally, he admitted that some Lock-Rights just don't work well in certain differentials, with the Sterling 10.25" being one of them... Basically it is a gamble if it will work properly or not.

My next choice was to install a Yukon Grizzly (their version of a Detroit Locker).
That was more than 100,000 miles ago and the only issue I have had is the 3.73:1 gears are a tad howly.
I have changed the lube four times since initial install, with the first two happening after break in miles, then again after a long haul to the East coast and back, otherwise I has been normal maintenance.

I would recommend you get a Yukon Grizzly, install it, and forget it beyond lube changes.
Money well spent in the long run, and you get useful traction all the time.

There are a couple oddities with the Yukon locker.
1) Both rear tires wear a bit quicker than with the open differential due to the skidding around corners more than an open, but the Yukon does allow slipping the majority of the time
2) Both rear tires wear relatively flat across the tread due to the locker too... This makes tire rotation easy to remember each season (I use winter tires and summer tires)
3) Occasionally, under certain conditions, you will experience throttle steer as the locker engages/disengages or stays locked while cornering.
This had only been noticeable when the truck is unloaded, or lightly loaded in the bed only, and while traversing long curved on/off ramps like some highway exchanges use.
There is one I drive many times per week that is basically a long, sweeping curve at highway speed and this is where I experience this anomaly caused by the locker.
4) Sometimes, very rarely, I will hear/feel the differential locking/unlocking in a harsh manner when driving on really slippery winter roads when one rear tire has a lot more traction than the other. Usually when slowing to a stop and an intersection and when one tire is basically on ice and the other having some traction... but this is rare. The clunk, however, will get your attention.

Never have any of these anomalies caused anything even remotely dangerous in terms of driving response and feel. These are just things I notice because I notice these things. I think most people would just drive and never give it a second thought.

Anyway, I have over a hundred thousand daily driver miles with a Yukon Grizzley locker in my 2wheel drive, 3/4 ton truck and I believe it has made my truck better, and safer, to drive year round in Minnesota conditions.

I have heard some rumors that Yukon has changed in quality over the past few years so look into that because mine is pushing 15 years ago that I purchased and installed it.

I will be finishing a car with a bare painted floor for a race car style interior.
In this case the color will be black if that color presents certain options.
What paint do you recommend for this interior floor?
Durability is the most important aspect.
Thanks, and have a great day.

I've got one that was painted black at the factory and is now mostly surface rust and some old paint left.
I believe it was from a 1966 289 engine in a Galaxie 500.

You could get that chrome plated if you want to go that far.

Good thing you arrived where you want to be.
I have some machine tools in my shop, including lathes and a small mill, but taking those out of the mix I would have likely cut them down carefully with a hack saw and then finished them with a wide file to arrive where you are now.

Or I would have used a fiber cut off wheel on a Dremel to remove the bulk, then a file to finish the part.

Your new freeze plugs will look perfect once installed.

Sometimes the inverse of the question helps to clear things up a bit.
The current question, "Is the secondary diaphragm balance tube needed when running dual quad carbs"?

The inverse question, why should I remove the diaphragm balance tube? followed by the question, what will I gain by removing the balance tube?

A quality electric water pump will work great for slow engine speeds and city driving conditions because the electric pump pumps at full capacity if it is on.
Many electric water pumps do not have sufficient flow capacity to keep up with an engine when driving at higher engine rpms for extended periods of time, like going down the highway.

But if you are having cooling issues at idle speeds, or slow driving speeds, I would look at airflow through the radiator (heat transfer and dissipation) before I would go after the water pumps pumping capacity.

Concerning plumbing a heater hose into the thermostat housing, that sounds like a problematic situation because the heater hose water flow directly in the thermostat area would likely give false engine coolant temps to the thermostat, likely making the thermostat react as if the engine is cooler than it actually is.