MG ZR: Cams & Maps

[Dum-Dum]

Essentially - unless you really know what you're doing with cylinder heads, getting friendly with the dremel usually ends in making either no difference or making it worse.

I've read and read about it, still I wouldn't take a dremel to my own NA Petrol cylinder head, you're likely to do more harm than good!

TBH these days I probably wouldn't trust anyone doing it by hand. CNC head porting is the way forward every time as the results are entirely repeatable and with computer modelling you can see exactly what the flow will be like under any given circumstances.