383 Cam Selection

Still working on my 383 build
Thinking of going with the Flat Top Pistons & AFR 195 Heads & CC 280 XFI Cam
FLAT TOP 5CC 12.257 CR & 280 Cam (69) = 9.44 DCR 196.7 PSI Cranking Pressure

Does anyone think the DCR will be too high with this setup. I'm not keen on going much bigger with the cam as I'm unsure how well it will tune to pass emissions in the UK.
We have a sniffer test with no visual stuff other than Cats.
I have to pass a
Fast Idle Test 2450 - 3000 RPM
CO% < 0.300
HC < 200 ppm
Lamda 0.97 - 1.030
and then a natural Idle Test 675 - 1375 RPM
CO% 0.500

Any suggestions as to how large I could go cam wise with regard to tuning.

Thanks
Mitch