My engine is shaking at a high rpm, I need someone that builds performance

[Billy M]

engines to walk me through this.? I have a high performance 355 chevy. It was running fine this year but all of the sudden the engine has been running rough. It runs fine if I accelerate slowly (keeping the rpms down) But as soon as I punch it the engine shakes as if I have a rev limiter active. I already replaced the plugs so that eliminates a fowled plug. The only thing different I can think is within the past week I got new gas and ever since then It hasn't wanted to idle until it heats up. Im thinking that because I only have a quarter tank left maybe there was water in the gas I purchased and that is now starting to get back into the engine. The other thing I was thinking is I neglected to hook up a vacuum line and it caused my engine to run lean. This would cause bolts to loosen (which did occur) and my distributer turned. I set the timing as best as I could but it's still doing the same thing. I doubt it's the timing so now Im concluding it's bad gas. Everything on the engine is new (intake carb heads pistons rods rings bearing etc) so that rules out wear and tear. Anyone have any suggestions. I just need to bring in another mind because besides the gas problem Im stumped. I plan on draining some of the gas tonight to inspect it but until then I have hit a dead end. Thank you