Porting stock heads

[Vip18971]

I came across the idea of porting the stock Iron heads on my 89 302 motor. I like it, because its cheap (it'll be a homemade port job, I know someone who'se really skilled with a dremel) which saves me money towards my 351 engine.

Anyone ever tried this, know anything of the potental, how effective it is, and how exact the ports have to be to prevent the car from running like crap? I guess there's some sorts of sheets that you put on the intake and exhaust ports which you can use as templates for the port job, but I'm more worried about all the runners inside that will be ported, I don't know of a way to keep them in line with eachother.