I'm running BC 272s on stock springs, but it's probably not recommended.

T Series Boost said:

I'm running BC 272s on stock springs, but it's probably not recommended.

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So probably 264?

You need to know coil bind for the stock springs so you don't get to much lift on the cam.
See these.
and see the attachment.
What are your goals here?

If it says anything some get away with BC 272’s (not all 272’s but I should say the less aggressive ones like BC) on stock springs, some do not. I got away with it, however on a bigger turbo (Borg s363) I was seeing valve float over 7k rpm. Obviously wasn’t an issue on any of my 16g’s as it was pointless to rev that high but noticed it there. Even going back down to a 14b I’ve still opted to upgrade to Evo 8 springs and retainers as cheap reassurance. 280s of any sort on stock springs are definitely a no bueno. I think what you need to observe here is the rest of your set up and what would be the most optimal cam selection as a 264 of any sort is a big jump from a 280 of any sort. For example, if you’re on a stock t25 even a 264 might hurt more than help over stock cams depending on other variables, if you’re on a PTE 6466 then a 264 wouldn’t be enough and you’d want to be looking at different flavor 272’s and 280’s and so on, if that makes any sense. The more aggressive the cam duration doesn’t mean the better the can shafts by any means. You go throwing 280’s in a 2g with a stock t25 it’s going to be horrendous to drive and a horrible powerband while making less power over what the stock cams would be capable of, to put it into perspective I’ve seen more than one situation on the dyno where various 280s have been too much cam for turbos such as the hx40 in a .70ar turbine housing or gt3582 in a .82ar housing even.

For a few extra hundred you mght aswel do the springs with cams. Its just peace of mind knowing they able to handle the not profile. You can get some BC cheap enough and even used sets for about 150ish, otherwise a 264 is ideal. 272 can be used as mentioned above but its not worth the risk without checking it all out to be sure.