Yesterday I fired the z up after sitting all winter. Battery was dead, had to recharge it. Finally got it running but it sounded like sheet! The starter was making noise like it needed shimmed. Never made noise before. After it fired it sounded terrible. I pulled the carb off and went threw it quick. looked clean gas smelled fine. Replaced carb and fired again but still running terrible. Back fires when i hit the gas, idles terrible, just sounds terrible. Just about out of gas so I decide to nurse it to the station. Not even a half block down the road I get a huge backfire and dead in the water. By dead I'm talking no power to anything. No dash lights no headlights no nothing. Not even tail lights. After scratching my @ss for a while I decided to jump the solenoid with a screwdriver. Starter spins but doesn't engage the flywheel. Did it twice and then all of a sudden my voltage comes back and I could start the car again. Fired it up and headed back in to the garage. Any ideas? Starter solenoid shot? Battery bad possibly causing low voltage to the HEI? Just wondered if anyone has any ideas?

Had a similar thing happen to a 68 Camaro. Drove me nuts!

Found that the ground wire from the firewall to the engine was dirty and loose. Cleaned and installed. Power checked good.

As for your propblem, check all the connections from the battery back for dirty, loose, or missing connections. This quest would include both positive and and grounds.

Check under the distributor cap. There could be moisture, corrosion, worn parts. Check for stuck mechanical advance weights (they are never maintained and therefore will rust and then stick).

Follow Cardinal's advice then put some fresh gas in it.

It sounds like the major problem is electrical (low voltage to ignition) but it may be running poorly due to old crappy gas and possibly a fuel tank sock or fuel filter getting plugged up from sucking it off the bottom of an almost empty fuel tank.

Check for rodent damage
My 2000 truck had intermitent engine prob.
Mice ate injector wire

Any chance mice got up under the hood and chewed the insulation off some of the wires?

Distributor was new last summer, had cap off everything looks like new, gas is fresh, filter is clean. As for mice I don't think I've ever seen a mouse or any sign of them in my garage. I'm leaning towards low voltage too. I just wondered if there was anything else i might have overlooked. Hopefully it's a bad battery. Gonna take it to napa and have them test it.

Do you have a Holley carb? even after rebuilding it, with the bad gas and the backfiring, you possible blew-out the power valve.

Usually when we store a car away, we'll drain the gas, pull the battery cables and put the battery on a Battery Tender and pull the carb for rebuilding. Also, we'll pull the plugs and give a couple of shots of Marvel Mystery Oil in the cylinders then depending on the plugs, clean or change them. One of the last things we do is get a dessicant bag and put it inside the interior to prevent mold and mildew build-up on the interior and cap off the tailpipes. You might be asking why cap the tailpipes? It's because we've had rodents and critters crawl-up and get into the mufflers then either get trapped or leave things inside that stink when you fire-up the car. Not a pleasant scent!

Power valves are fine......Holley 4010, power valves and jets come up threw the floor of the carb. never hurt one in these carbs from backfire. My Garage is pretty much rodent tight. Still leaning towards battery or starter.

If you follow the given advice and find it all looks OK, then also check your fusable links. Make sure there are no frays or naked wire showing anywhere in that main harness. As for it running bad, have you pulled a plug or 2 to make sure they aren't fouled? How long did it take before you "finally got it fired"? It's possible that with all that pumping the gas pedal, you may have fouled the plugs.

Good point! I'll pull the plugs and have a look. Still doesn't explain why it backfired and lost power to everything behind the starter though