Any good/bad experiences with cutting tools and sanding tools for porting on cast iron heads? What cutters have you found work weel? What styles? Thanks.

x2 on a carbide burr ... a carbide CUTTER will walk-around too EZ ..

Mondello sells good cutters. Many different shapes and sizes.

http://www.mondello.com/pages/toc_1.htm

http://www.ruffstuff.com/pages/carbide.html

I like the oval, shape E burrs. Double cut, 6" long in a variety of sizes. You can get by with just a 3/8", but a 1/2" speeds things up in the long straight stuff, and a 1/4" can make the fine tuning around the guide boss much easier. Those are the three sizes I recommend. Obviously do not start the burr unless it's against some material, do not free spin it (in other words, not have it against material when you're spinning it at speed). You'll want the walls to look straight and as smooth as the burr will get it before you ever touch it with a sanding roll. For cast iron I like 40 grit sanding rolls, but if you spin them too fast they tend to come unraveled. 60 grits hold up better but they don't remove material as fast. I like a combination of 40, 60 and 80 grit. When they start to leave black smears across the port, put a new one on. Trying to use up the whole roll makes for a frustrating port job.
Also, having a good grinder makes the job so much easier. The Suhner grinder (the expensive one) on the website I pasted in is pretty much the Mercedes of all porting grinders. Milwaukee makes one, but your forearms will feel it and they tend to be burr benders as they spin up immediately and only have one speed. Air grinders work, but you don't have as much control unless you get one of those long air grinders, which I have had no experience with.
Grind away!
One more thing! Have a spray bottle of light oil on hand. It'll make the burr last a lot longer. And have your shop vac ready to vacuum out the cuttings. A fan set to the side of the head blowing across it works pretty good to keep the dust out of your lungs and eyes.

Indeed. That metal dust is some tough stuff to breathe.

I'm curious, why do you not want to spin up the cutter before touching the surface?

Thanks.

I don't like porting heads, but I put a piece of 3/8" fuel hose over the shank of my long carbide burr. I found it useful for using it as a guide to control the cutting end.

If I port another set of heads, I'll try using my mill to do most of the work. I don't know how that will work out, but if I can figure out how to program a port, I wouldn't be doing the hand work as much.

I wouldn't have thought a cutter on a mere 6" shaft would bend like that, but I can believe it could happen.

Can anyone recommend a decent electric die grinder ? I won't use it much, just occasionally to clean up the ports, gasket match, or debur a block or two.

I used to use the Craftsman die grinder - back then it was the only reasonably priced one out there. Problem was it got too hot to handle after short use. Also, get one with variable speed ... you don't want to be doing everything at 25,000 rpm !! For minimal use maybe check out Harbor Freight !!

http://www.mcmaster.com/#carbide-burs/=esnx3n

double cut is what you want

I suppose that if I have to spend $100 on cutters, I might as well send the heads to Muscle Motors and let them port and rebuild them?

Paying a pro is well worth the $$$ in my opinion.
I have done my own and had decent results by not going overboard.
It is hard to quantify because I also did some suspension changes.....it was an over the winter project that netted .15 on the E.T. , but what helped most is hard to say.
It picked up 3-4 m.p.h. in the eighth though , and that indicated motor over suspension I think.
I have an old Makita electric ( Japan ) and it is a war horse , but as production went over to the Red Menace , quality went south.
Same for Milwaukee , and probably every other tool maker.
If you are going to use it , buy quality.
If it is a one shot , buy junk.