Using a MAF calibrated for a larger displacement engine is a very bad idea. It will leave almost no room to tune idle and off idle running (read below 2000rpm) as the MAF not be calibrated for such low kg/hr draw points and start at what a larger engine would draw at low rpm levels.
Also you will only be using about 2-2.5 volts of the 5 volt spectrum so the rest of your tuning will not be as precise or consistent.
