240z engine help timing

[Guest freebird]

I have a 72 240z with a l24 that i recently put a 4spd manual in cuz it was auto but anyways the car runs and idle but when you give it gas it hesitates and pops a bit. I think timing and the carbs have alot to do with it but what I really want to know is how to set the timing. I put a timing light on it a turned the distributor and the marks on the crank pulley disapeared but it appears to run better.