It's almost as if my post will be useless, because I have no real world experience with either cam. BUT The lift on the Cosworth 272 are actually higher at 11.0 mm lift, than the JUN 272, where lift is 10.8. I think the ramp on the lobe is more aggressive for the JUN 272. I suppose you could look at the M3 MIVEC cam if you want to go even more aggressive than that. You'll probably need the head ported and polished for the the M3's, as they are 280's and 11.6mm lift for the intake, and 272 at 11.0 mm lift on the exhaust. These would defiantly give more top end. Vivid Racing has them.

 

The ports on a stock head (both sides) begin to choke around 10.2-10.5mm lift. Unless the head is demonstrably ported to take advantage of higher lift cams, the higher lift won't provide a potential benefit.

The JUN 272s are tough to beat for a stock head and large turbo. The long effective duration ("272" doesn't mean much) makes them very good high rpm performers.

 

I didnt see the M3's on Jun's website

 

The M3s are Cosworth not Jun (eventhough that there is a close relationship between these two... Cossie makes Jun's pistons and who knows that else...)

I am in discussions with Vividracing who first advertised the M3 cams and actually i am waiting for a full Spec sheet before i order... I already have the M2s...

The M2s are:
272in / 272ex - 11mm for both and effective duration 255 degrees @ 1mm lift for intake and 225 @ 1mm lift for exhaust...

The M3s are:
280in / 272ex - 11.6mm lift for intake / 11mm lift for exhaust but i dont know if it has more effective duration than the M2s...

will wait for Vivid or Cosworth to get back to me...