see iv been woundering what size to make the ports and as for the machining thats no prob as to i am a machinist by trade and know alot of ppl and there shops i can use for free i dont think it would be to hard to do a PP the only thing that puts me a bit off is timeing it as in where to drill the big hole and how big to make it lol.

 

step one is to buy a degree wheel. summit, jegs... its cheap.



step 2, the factory port timings for the mazda housings are out there. plus a couple of SAE papers on the racing engines.



with a degree wheel and the port timing, that basically gives you the port size....



BUT the factory port timing and sizes are for the RACE cars, ie the power peak is 9000ish rpms.



if you want to move the power peak down, then the ports need to be smaller