Are aluminum heads worth it?

I'd say with the numbers you post now there's more in it. You can keep bolting on parts, but untill you learn how to make it work, it will never be as quick as it should be. So - yes, thyey are worth it. But no - not until you've maxed what you have. A 360 in an Abody with a mild cam can run deep in the 13s. With gearing and a convertor into the 12s. Is there a mechacnical issue with the engine now? Like a bad cylinder or smoking or something?