Hey everyone, this is my first post on this forum. I have a 75 Dart Sport with a slant 6. I've been driving it with only minor issues for the past year up until the beginning of the summer when the car began idling so bad that it was undrivable.

Checked the hoses for cracks (none found, they don't appear dried out or old), replaced the carb base gasket, put in new plugs and wires. The starter was recently replaced with a rebuilt one but now the car won't even start. There was only the machine gun clicking noise coming from the starter when I turn the key.

Battery tests 12v with my multimeter. So I replaced the ancient starter relay, turned the key and a spark shot out (of the relay) and there was smoke.

I'm not a mechanic, I just love old cars. It's pretty frustrating not being able to drive her all summer and any advice would be greatly appreciated. Thanks in advance!!!

Check your engine, body and battery grounds.

Electrical is my Achilles heel, but THIS much I do know...
As stated before, make sure all the electrical connections are good and clean. The thick wire to the alternator needs to be secure, make sure it is not loose. The negative battery cable connects in 3 places: The engine block, the Negative battery terminal AND a thin 6-10 guage wire to the radiator core support. The collection of wires that enter the bulkhead connector at the firewall can and do deteriorate over time. The corrosion that forms in there will require MORE voltage to start the car and lead to other problems in the future. I hope this helps.

Thanks everyone, I will be checking your suggestions tomorrow when I have time and I'll update.

Already cleaned battery posts and put new clamps on the main wires

Did you check battery condition or or hook up a load tester???

Thanks guys. I jumped the battery and got it to start with lots of gas, but still idles very rough. My friend helped me check the timing and he said it was close enough to what it should be. Replaced carb base gasket already, I think I am going to try to rebuild the carb. It's a 1 barrel holley, appears stock (holley 1945 I think?) but I can't find the numbers on it online to get the kit.

Numbers on the carb are like this:

6260 2
1240

I just want to make sure I get the right kit, never done this before. Thanks!!

it will run rough if the battery needs a charge or if the cables are so corroded that htey create a poor connection.

You may have to consider that your car eventually has more than just one problem.

You may have also a problem in your wiring. May be it was before or you did it when smoking that relay.

Measure the voltage of the battery when disconnected and read what changes as soon as you connect it, switch on ignition and start engine.

Sometimes it comes to a point where you will be happier to give it in the hands of a mechanic - for once.

hope by now you have your elec. problem solved.
as to your carb,your #s indicate a holley 1920
built 5 1980.both carbs do a good job and kits are available from any of the part stores.see pics for difference.please be aware the # 1 problem with slanties is the intake/exhaust leaking.swing on over to slantsix.org it is extremely important to
install the int/ex gasket correctly.we love our
leaning towers of power.

Thanks for the info and diagram kd, it's very helpful!! I am going to rebuild the carb, then try replacing the manifold gasket if my idle is still poor.