Sniper

Your friend has no idea how the ammeter circuit works. The only current it should be measuring is what is going to or from the battery, not the fuse panel.

Sheet metal isn't the issue, again, if I recall correctly, but rather the frame itself. Measure the clearance between the top of the spring to the frame, then subtract the height of the axle and attaching stuff, that will give you your clearances.

Your pictures aren't loading. I had a 38 Plymouth, decades ago. IIRC, the distance between the frame rail and the axle tube would be minimal after this swap.

I test batteries for a living, well I do other things too but that's one of the things I do. Do you have a meter? If so get me the following readings. With the battery not connected, what is the voltage on the battery terminals? (this is to see if the battery is fully charged) With the battery connected, but nothing turned on in the car, what is the voltage on the battery terminals? (looking for a drain in the electrical system) With the engine not running and the headlights on, what is the voltage on the battery terminals? (load test of the battery, light load) With the engine running and nothing else turned on, what is the voltage on the battery terminals? (checking the charging system) With the engine running and the headlights on, what is the voltage on the battery terminals? (checking the charging system with more load) With the engine OFF and the ignition disabled, crank the engine over, what is the voltage on the battery terminals? (maximum load test on the battery) When using a charger to charge the battery the charging voltage has to be above 6.44V, so you can hook your charger to the battery and measure that as well.

Wait you have the thermostatic fuel gauge a different animal than my 51's.

So, why could a 0.185" spacer not be used between the flywheel and the crank? Shouldn't be an issue for a competent machinist to make one up?

Not sure how well a 12v negative ground converter will work being fed by a 6v positive ground system when the sender uses the chassis ground as a path? I'm think smoke will be released.

I did assume an aftermarket 12v gauge

There are multiple states that have adopted California's nonsense. https://ww2.arb.ca.gov/our-work/programs/advanced-clean-cars-program/states-have-adopted-californias-vehicle-regulations

Not simply

That's how it starts. We're just asking questions is all.

My house laptop is still Win7, garage one is XP, lol

Oh yes, I forgot that part. Take out the vent, clean up the area well,, test fit the gasket all before you glue. And lube the pivot points, my vent was froze up when I bought the car and actuating it was actually causing the cowl itself to flex around, I am kind of hamfisted, lol.

7 to 1 compression ratio. Atmospheric pressure is 14.7 PSI. Rounding up to 15 * 7 is 105 PSI.

Yes they must be glued down I recently replaced this gasket on my Plymouth. I used 3M weather stripping cement in accordance with the directions on the tube. One piece of advice though is used two people to install that gasket and make sure you touch it down where you want it cuz once those two pieces meet you're not going to move them to .ake any adjustment

Load testers are not that expensive. I have one for work and yes it's a fancy expensive one with them at Harbor Freight for a reasonable cost actually the best load tester you can get is the starter

it could be a bad charger? I had that happen to my lawn mower battery. It was low I put my charger on it let it charge overnight still didn't work so I grabbed my other charger put it on in less than an hour it I had a running mower

valve adjustment will affect compression readings too. My 51 had around 50psi per hole when I got it, 4 years later it's still at 50. I need to adjust my valves

lol, there's plenty of that on this site. I did a review on the Rusty hope conversion. https://p15-d24.com/topic/56787-weekend-work/

I am not sure that colored wring diagram you have is correct. The coil power needs to go thru the ignition switch, it doesn't in that drawing. The battery sin;t hooked up to teh generator output in the drawing either. Both of those are wrong. So I dug out my FSM's, they show the same for a P15. So I grabbed a shot of the P-17 diagram and it shows properly. Your corrected hand drawing is good. The fusible link should probably go between the ammeter and fuse box connection.

Did you verify the float settings and float operation? Usually, when I see this either the float is improperly set allowing fuel to over flow or the needle isn;t shutting off the flow. Occasionally it will be too high fuel pressure overcoming the needle

All loads need to be on the generator side of the ammeter, not the battery side. The only thing you really want on the battery side is the battery. The ammeter is there to show the state of charge to/from the battery. Any other load on the battery side of the ammeter will show a discharge on the meter. In your drawing your charge wire needs to move to where your fuse wire is, keep the fuse wire there. If the meter reads backwards, swap the wire on the ammeter.

Did you install the side seals too? Did you install the seal so that the open side of the lip faces in? Should look like this (not a mopar application shown, but seal direction is the same)

I go to NAPA, in person Unless it's a Sunday and I have to have it. I use Rock Auto when it's not time critical and I am shopping for best prices. I use Autozone for used oil. Lol. Actually, I tend to buy my Chemicals there,

In order to save money with effort one has to have the skill set to do that. That right there kills more projects than anything else. Someone tears into a project, then realizes they are in over their head and the project dies, sold off or stuffed into storage to "get around to it" one day.