need help with building M50 NON Vanos

Hello, i'm planning to start budget engine build soon, i've m50b25 block with 2.8 rotating assembly and b20 non vanos head(it has 80mm chamber), my opinion looks like this: boring b25 block to 86mm putting 86mm pistons in it (from opel c20xe engine, i can get it cheap here ) 135mm rods m52b28 crank and b20nv head + porting, i know b25 head flows better but this is my only option at this time. i want high cr but i dont want detonation ofcourse, i'm using 95-98RON fuel, will this setup work for me? please dont tell me about buying s50 or something like that, cause in my country s50 costs like 3000$, while setup that i've written here costs me 300-400$ max

need help with building M50 NON Vanos