Ignition Timing: N/A Stock vs. N/A Stroker?

[Pedaaa]

Hello,

what would be a role of dumb for that?
If i have a good ignition map for a stock M20 2,5L, how do I need it do modify it for a 2,7L stroker?
(assuming CR would stay the same)

Do I need to advance or retard ignition generally?

[jlevie]

If the compression ratio remains about the same and you are using the M20B25 cam, ignition timing should be the same. If you increase the CR you'd want to advance the timing slightly (and run a higher octane fuel).

[Pedaaa]

Thanks!!