First let me say that I'm not a big gear head. I don't know a ton about cars and their engines. I purchased this project as a learning tool to help teach myself some auto repair but at the moment I'm a bit stumped. Vehicle: 1971 Toyota FJ40 Land Cruiser Engine Block: 1971 Chevy 350 V8 from a K10. Engine Heads: Who knows, but they're from a newer than 71 chevy. Carb: Holley 4 barrel Anyways, 2 weeks ago I went to start up the FJ and experienced a loud back fire. I restarted the engine and was able to drive. As I drove the engine began feeling as if it was running down a couple cylinders. I parked for the evening (Out of town at my parents house) and decided to check my plug wires and plugs. All the plugs looked fine and the wire didn't look to have any physical damage. I left their house and drove home. If I pressed the pedal harder and got it higher in the revs it seemed to smooth out and drive fine. I made it 2 blocks from my house before it died. I got towed into my house and went back to the drawing board. My first attempt to get it back running right was changing the HEI distributor cap, coil, and rotor. This restarted the FJ but I had to press the gas pedal to keep it running. Black smoke was coming out the exhaust and the carb started flooding. Literally flooding gas out of the carb. After looking online I found that Holley is notorious for blowing powervalves after a backfire. So I replaced the power valve, metering block gasket, and the fuel bowl gaskets and started it up again. This time it was able to idle but it still has a major shutter. I rolled it out of the garage and reved the engine. It never really smoothed out. I pulled it back into the garage and let it sit. Does anyone have any ideas as to what my issue could be? On my list of possible problems... Timing - I have a timing light but I can't seem to find the timing mark on the flywheel... The whole distributor is toast vacuum leak? not really sure where to look to figure out if the vacuum system is good. Are any of you masters of the 350? Generally good mechanics and have an idea where I should start? :thumbup::thumbup::thumbup: Thanks in advance!!!!!!!!