Could happen, just depends on how well the parts are matched. I have a TF intake on my engine which is a better design than the M1 but a ported M1 might work pretty good. My cam is a hyd roller and a touch smaller but it all depends on the combo. The TF heads work pretty well with some cams and don't work so well with other cams. Who knows how those heads will work once they've been ported. If all the parts are working together then it could be a 625/650 engine.