OK the 103 is the 103rd day of the year it was built. Means nothing for parts.
I love the ignorance about thermoquads. I have 2 of them for my 340.
You can find the correct parts if you look hard enough on ebay and online.
Here is a pdf for the manual to rebuild and tune
https://www.carburetor-parts.com › ...PDF carter-tq-manual.pdf - Mike's Carburetor Parts
You also need to reglue the transfer wells for the primaries with JB Weld Marine, there are tutorials on how to do this
I would not try to manually modify any parts since they will never be precise look for original parts.
Here is the online Bible for id's A Carter Thermo-Quad Guide
I would start small on jetting, primaries are available. .090 and 0.127 for secondaries. Leave the rods. And only change 1 thing at a time for tuning. Go up 2 steps on primaries always 1for secondaries
Adjust rods for drivablity.
The dash pot is essential for the secondaries. It needs to pull the door tight with vacuum, the door should be 1 1/2 turns after making contact with boss in back.
Look for the secondary tool using 2 screw drivers sucks.
Use only x rings for primary seals.
The tree should be 1 /2 turns from the bottom.
They need a lot of choke to start.
Mixture screws should be 21/32 to 24/32 from base to top of screw as baseline.
Honestly i would look for something starting with a 6xxx since these are pre lean burn and are a little easier to tune. You can use parts of the one you have.
