Hi mate
Assuming "500+" means 500-550hp (and not 1000hp) I would consider your engine over-cammed with 272s. That said, they're not a bad thing to have and make everything a lot more efficiently and achieve a given peak power level more easily (ie same power at less boost, or more power at the same boost).
You could still make 500-550hp fairly easily with 264s but honestly you will notice a very limited difference in your low-down in changing from 272s to 264s... and even less so by only changing your intake cam. You really need to build a complete setup rather than change one part out and expect a big improvement... so a well matched turbocharger, well selected turbine housing option, cams selected around a particular boost or power level, porting work as necessary, etc.
Depends what you are trying to achieve - maybe set out your goals and look at a group of parts to see if there are multiple areas that can be addressed at once.
It's like asking if you'll be better looking with a haircut.... yes maybe but if you have no teeth then you still aren't getting laid! So look at the big picture.
