If you guys use electric Dremells rig up a Cieling fan rotary dimmer switch to use as the speed controll, The best Dremmel is the 2 amp Makita with 1/4\" inch collet. it's nice and light and big enough to hold properly with both hands(that's the draw back of using air grinders, too small to hold properly when heavy cutting) and the electric has gobs of torque. (around 175 bucks)
My method of port matching manifolds reguires the guides to be out of the heads as you perform the final match up with the 2 bolted together, and I use a 60 grit Cartrige roll on a 6\" shaft through the intake port on the head. It takes a lot of practice to get the speed the grinder controll so you don't dig trenches or bend the long shaft bits. Once I am happy with the fit I separate the Two and then use an air Dremmel (also with speed controll) with a Long 1/4\"shaft with a slit cut in the end to accept 80 Grit Emery paper (a strip about 5\" long rolled up clockwise on the end, I spin this through the port with a cutting fluid, ( Home made mix and top secret ) and it's not WD 40!
) You have to get the speed just right to get the real showy finish... Like Hans Says The final finish isn't the be all end all but I call it \"out of the box appeal for the customer\", if you pay the money you hope it will look great right,? So I try to put a nice clean 80 grit finish on all my intakes. ( I like Standard abraisives emery as it has a real flexible cloth bach a the difference in final finish is noticable.
How far to port upwards? It depends on the manifold and the port on the head,in a nut shell a correct port will have a slight reduction in diameter all the way from the butterfly on the carb, to about 1/2 inch below the valve seat. if your intake track starts big, gets small, then gets big again or anything like that you are changing the intake velocity and this is not good, a nice tapered intake track accelerates the intake charge. ( so on this one I diagree with the \"Old One\")
Food for thought if you plan on porting you own heads for the first time, Grinder 175 bucks, Speed controll say $10, Air Dremmel another $ 50,
I use 7 different Carbide burrs primarily all with 4-6\"shafts these will run you 30-50 bucks a piece for good ones, Then theres the cartrige rolls and Mandrells,and .....and...and....
The FYI on the Standard abraisives website is also a very informative how to ...
Happy grinding to all,
If anyone wants me to flow test thier heads(only Type 1) I'll do em for 25 bucks and that includes a graphical print out out (and we can compare to the hundred or so flow test from different VW heads in my ever growing database)
Chow for now. and have fun grinding!