head work for a 1.6
 

I've decide to do a rebuild on my 1.6. The plan is for new m-tuned rods,and I haven't decided on pistons ( a lot of piston controversy in threads for a sub 300 whp build)

I've read that the 1.6 head doesn't flow a lot of air. Is it worth porting the head for this power goal? I'll be running a china 2871. I can get a head that has already been rebuilt for 150. If porting is worth it I'll just use mine. What rpm is stock head good for? What are it's limiting weaknesses?

I also don't hear about anyone swapping in new cams with higher lift. How much lift can the stock springs take? In my mopar 440, a cam and rocker arm swap makes a huge difference int the amount of air in the chamber. There was mention in a thread that and adjustable cam gear set was as good as new cams. i don't know if I buy this, but I am not knowledgeable on the adjustable cam gear so I can't refute this claim.

After all of this jaw jacking. Should I buy stock head that has already been rebuilt, or have new oversize valves and valve job done on my current head?