Now to get the engine electrical sorted. I switched to a powermaster starter that only has two terminals but that's not really a problem. The main issues to solve were 1)deteriorated original wiring going to the starter, and 2) altering the wiring to remove the resistor circuit for the points ignition so I can get a full 12 volts for HEI.

The factory has a pink 12 gauge wire supplying voltage but it hits a plug under the dash and from that point turns into a 20 gauge resistor wire, it is a solid core wire, not stranded, and is contained in a woven conduit. I frustratingly went the wrong diriection in the harness looking for where it terminated because for some odd reason they make it take a Y in one direction, then loop it and have it mysteriously go back the other way--this is while it's in the engine bay. I figured that out and found it in fact goes through the firewall as a resistor wire, so that's what I looked for under the dash. I will not remove the resister wire from the original harness.

I don't ahve any 12 gauge pink wire so I'm going to change the circuit to a 12ga yellow wire from that point and that wire will do two jobs: 1) provide a "switch" voltage for a relay that will activate an auxiliary fuse panel under the hood, and 2) give the HEI 12v unfused, picture 1 and 2 show the odd loop of resistor wire that led me in the wrong direction.
Pic 3 shows my special homemade wire splice. I covered the splice in hot glue , it's an experiment.

 

The factory wire that activates the starter solenoid "S" is an oddball. It is colored violet. but most notably there are 4 total wires that go to the starter and while they aren't perfect, they generally held up very well to the heat and time. 2 fusable links are also used at this junction at the starter and they are worn but usable.
But this 12 gauge Violet wire for the S terminal is in horrible condition. The jacketing or insulation seems to be made of different material. I assume they got that wire from a different distributor and maybe the compounds they used for the insulation was not up the the task, The other wires jacketing is in much better condition.
I found a 10 gauge purple/violet wire in my garage and chopped off the factory wire going back a foot or so and installed a new section going to the starter.

Pic 1 shows what remains of the original wire, the jacketing is almost gone, crumbles like old bread, and its also almost impossible to see what color it was unless you go back several inches. Even though it was wrapped in tape wrapping it still deteriorated.

pic 2 shows new section installed.

 

9/14/25

I wanted to add an auxiliary fuse block underhood to power radiator pusher fans, replace the factory wire/30A fuse that powers the blower relay, and power the factory "main power wires" that go to various places. I found a 12ga pink wire under the dash that changes to the "points ign resistor wire" while under the dash(it changes at a connector), and is apparently the only "ignition switched" power wire. I found it hard to believe but it was the only wire I could find in the diagram/harness that would be a good trigger wire for some kinda relay. But because the form it takes underhood is "resistor wire", I needed to find and splice it under the dash where it was still a normal power wire. I'm using a HEI distributor and don't need the resistor wire anymore.

Eventually I got it spliced and routed to a relay, which takes power from a "terminal block" I got outta a junkyard GMT400. This terminal block was wired with two 10ga wires that are loomed together and stretches between 1) the terminal block, then goes to 2) the alternator, then goes to 3) the battery. From that terminal block it sends power to the relay which is now switched ign power, I also have a 16ga fusable link between the terminal block and the relay. That relay powers a cheapy aftermarket fuse panel. That fuse panel powers a 30A heater switch relay wire, 30A pusher fans, and I'll use it to power gauges inside the car, and other stuff.

I also have the HEI powered by the main GMT400 terminal block; unfused because the internet engineers said so.

I lastly made a stretch of loomed wire to be used in the future as a radio wire set. 4 wires because I was advised to do that. It stretches from the dash, under the carpet, to the rear seat area and into the trunk.

First pic shows the TAPECASE wre loom tape I use, from Amazon. It's the best I've used by far. do not get the extra wide roll, it was a stupid idea, didn't work
Second pic shows relay and connector; I switched out the main power wires with 10ga blue.
Third pic shows the custom harness" of double 10ga wires running between GMT400 terminal block--alternator--battery.

 

First pic shows how i clamp one side of a series of wires that I'm gettin ready to wrap in factory looking NON ADHESIVE wire tape. DO NOT EVER USE ADHESIVE-STYLE TAPE. bad and messy idea. Won't last. I learned that many years ago.
Second pic shows the wires for the radio from dash to trunk getting ready to be loomed. I clamp one side to sit stil, and the other side to a wheelbarrow to adjust tension,
Third pic shows it completed. I think total footage was 12'; it took me about 15-18 minutes. Came out nice.

 

10/3/25

Exhaust. The car cam with the original exhaust for the old engine, and part of the exhaust mounts to a mount based off of the tailshaft of the trans. Since none of that was there anymore I was gonna have to figure out what to mount pipes to.

I was originally gonna try an fabricate the entire exhaust system from scratch with piping from Oreillys but I quickly scrapped that because it'd be too time consuming. So I decided to modify the original exhaust by any means necessary just to get the vehicle running and driving and I will figure out a more permanent system down the road.

The original collector from the manifold is 2", and where it Y into one pipe it goes all the way up to 2¼". That should be more than enough to handle my 500ci air pump. I'm told backpressure = torque so now my caddy will make even more torque than before.

I modified the collector that hooks to the manifold, I don't know if it'll seal, I hope it does.

 

I didn't document this next part well, but I basically cobbled together an extremely poor exhaust system and attached it with one small bolt to the trans crossmemeber, and then I hung the muffler from a factory exhaust hanger on the chassis, but used some garbage as the bracket.\

First pic is of modded collector at Y intersection
Second and third pic show further cobbling, just random sections of 2¼ pipe I luckily had laying around, I cut it and welded it together in a "strait" line. Second pic also shows tiny bolt to trans crossmember that holes up most of the middle area.
Fourth pic shows muffler, I actually just now realized the muffler is only tacked a few times, gotta fix that before I get on the road.
Fifth pic shows my rear hanger fabrication. I don't know what all those clowns at "Ringbrothers" think they're doing but it's wrong. The welding at the muffler looks extremely poor because it is, hard to weld upside down.

 

Update 10-6-25
Brother and I installed hood and front seat two days ago. Power seat barely works but it works. I have no pictures.
Tonight I got the guts and started the engine for the first time running it one bowl of fuel at a time. Ran it 4-5 times total, need to add more Trans fluid.

If you look at post 30 you'll see my plumbing for the trans cooler. It managed to only leak at ONE joint, that's it. I can't believe it.





EDIT 10-9-25
This aged poorly. It was actually the opposite, every joint leaked except one or two. All leaks were luckily found to simply be fittings not tight enough and no real horror.

I activated the climate control stuff(no refrigerant/Compressor) and to my amazement I believe it functions, not perfect, but air came out of different vents and so fourth. You could hear the transfer of vacuum under the dash and "things switching". Car hasn't ran in 43 years and is 58 years old.
to test leaks I ran engine for about 20 minutes at high idle(carb is stuck can't get idle down) and it held temperature, it varied between 195º and 210º, Thermostat is a 195º unit so thats exactly what I expect. The radiator fan clutch is a HAYDEN 2797 (Severe Duty), and at about 205-210 it would noticeably come on and cool the engine right back to 195-ish; I was very happy about that.

Next thing is to bleed brakes and take for a drive.





EDIT: 10-11-25
Bled brakes yesterday, small leak in a line I had to replace on the rear axle where it threads into a junction meeting the rear hose. Must be a bad flare.
Today I installed front seat belts; let engine warm up, add some trans fluid, and without further ado I slowly drove it around the block, even when moving the lack of PS makes it hard to steer. Drove fine, lots of rough edges to smooth out.




EDIT: 10-12-25
Drove it about 2 miles around the block again and again, maybe got up to 40. Doesn't like heavy throttle but it does what it is told. Carb is meant for Chevy 350 out of a 1975 truck and I got it out of a junkyard at least 8-10 years ago and then it sat on the floor in a bag for that much time before being put on a random 500ci engine and being asked to run and drive as-is. I'd say thats pretty good.



EDIT: 10-22-25
Drove it more the past week, Fuel gauge came to life a week ago. Engine has two belt systems, Front most V belt drives the alternator/water pump(and maybe smog pump?), rear most V belt drives A/C compressor and Power steering. I finally added a junk AC compressor just to take up belt slack and added the PS pump that came with the engine, after some bleeding it works great. Next job is rust around rear window channel.

 

10-22-25
The rear windshield was broken out long before I got the car, it came with a replacement glass. The rear windshield glass channel was rusted in the corners, specifically the lower corners, today I fixed the lower drivers. I don't want the body to be nice and perfect, so the metal doesn't follow the proper contours and won't be "level-able", I'm just gonna put some filler on top and paint it.

First pic is what I started with after sanding some surface rust off.

 

More pics.

 

Another rust hole on lower drivers rear windshield.

 

Two days ago I started and yesterday I finished the lower passenger corner of the rear windshield.
I forgot to get pictures from before.

 

The lower passenger had a couple other holes near it so I fixed them too.

 

Today I took a strip disk that looks like a sponge and stripped the major scaly rust off the roof, I left minor rust behind and will sand and prime over it.

Call me naive, but to my dismay I found that the front edge of the roof where it meets the top front windshield channel is extremely rust pitted, far worse than the rear window, and I am almost sure whats under the glass edge is going to be worse. I was really hoping the front would be nicer than the rear and less work but I'll have to try and get the front glass out tomorrow and see. Not happy about that.

 

Nice work , I am also working on a 67 ,but we're i am i can't find any caddy engines and or parts are very expensive. I am putting a 454 out of a 79 Winnebago into it right now and so far it's a lot easier then people had said. My issues is the engine is physically longer by 3-4inchs and hits the sway bar. I am using a th400 trans and swaping the caddy th400 parts into the case so the drivesshaft and crossmeber are in Stock locations.
I have to find some blocks to make the sway bay sit lower or find a kinked bar that will go under the braces.
I have very similar rust around the windows, seams to be a common factor. But for now i will keep an eye on this thread, seeing as winter in canada is setting in and my project is on hold till spring. Keep it up🤘🤘🤘

 

The was no rear windshield installed in the car when I bought it but there was a spare rear glass on the rear seat. The lower corners of the rear windshield channel were rusted from a vinyl top so that had to be fixed.

lower drivers rear windshield corner