Is It The Gas Tank?

[Bigcalhoun]

Gents,
My '70 302 seemed to be having a fuel issue of some sort. In particular, it was struggling a bit upon initial acceleration and at lower speeds. It seemed to be maybe a little starved for gas. I normally burn ethanol free gas to help reduce moisture in the lines. My solution was to run a can of Sea Foam through the tank and spray a can of carb cleaner in to the carb. It ran like a dream until the tanks got 2/3 empty then I get the same thing.

I'm starting to think the gas tank has rust or other garbage in it that is creating the problem based on it doing so well after the carb cleaning but acting the fool once the tank got lower. I filled her back up but still getting some kicking and cussing.

Am I on to something with the tank theory?

Thanks in advance for any words of wisdom.

[tsherry]

Probably. Drain the tank (I use an electric fuel pump with a line down the filler), and pull the tank. Fair chance that the ethanol/gas you've been running has "cleaned" several decades of crud from the tank innards, and is clogging up the pickup tube. Once it's out, drain the sludge out (probably also via the filler) into a disposable container(5 gallon bucket or three). Also, the fuel pickup tube could be rotted off, and only picks up fuel from the top part of the tank when it's full. I had one that looked like a sieve on the lower 1/3, so the truck would starve for fuel, even though the tank still had plenty of gas in it.

I used the Por-15 clean and seal kit on four or five tanks which worked quite well. The oldest of these cleanings is 10 years old, still no issues. You also want to replace all of your rubber lines.

Then, if you can, don't use ethanol gas ever again. "Straight" gas is "more expensive", until you actually run the numbers on mileage: Ethanol gas in my experience provides poorer gas mileage and poorer power; pure gasoline better mileage and more power. You get what you pay for.

[Bigcalhoun]

Good news on this post. After a new set of plug wires and distributor cap, it’s running better than it has in years. Such an obvious fix in retrospect. While there may be some junk in the tank, not the main issue it seems.

[tsherry]

Cool. When you're ready for an upgrade, drop in a duraspark 2, and be prepared for another jump in performance and quick starts.

[basketcase0302]

like tsherry said bout the duraspark, and...it's a pretty easy conversion.
At least throw a Petronix conversion in it, loved mine and went trouble free for years after installing it too.