Car: 1975 Dart Swinger
Carb: later model Holley 1945 (NOS not a rebuild)
I have done the fuel line mod.
Problem: extreme hesitation, stalling, struggles to get up to speed to get on highway. This all started happening today. Had the car out most of the day and it was horrible.
I installed the NOS Holley some months back. No real issues. Did the fuel line mod. Then I started having problems with occasional stalling and ocassional hesitation. I changed out my spark plugs (I have no idea how old they were). When I changed the plugs the car ran EXCELLENT. Zero issues. It ran like that for a month or so and now out of nowhere it is running horrific.
The air cleaner is fine. Thermostat, diaphragm and vacuum all work as they should. I'm fairly certain the vacuum stuff is good. The problems today were so severe I am worried it's something bigger than just a small adjustment.

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Fuel fouled? Bad rebuilt carb? Had one catch on fire at a stop light but it was a 1 bbl 225

do you always buy gas from the same place?

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-proud new owner of a '61 lancer 170
-previous owner of a '74 dart swinger (R.I.P.)
-coming here for some schoolin'

Is the carb tight to the manifold? Any leaks in the vacuum hoses?

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63 Plymouth Valiant V200 Convertible.
225, HEI, Super Six with 38/38 Weber, Electric Fans, Scarebird discs, FirmFeel front swaybar.

Did the timing jump? Check the distributor make sure its not moving.

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https://tinyurl.com/yynpj4v2

After some investigating it appears that one of the two bolts holding the carb down to the manifold was loose. Tightened it down. I spent yesterday adjusting carb. I am cautiously happy as I have now driven it yesterday and today with no problems. Thanks to those who responded. Much appreciated.

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