I was reading the article on siamesing the tpi setups. Good write up by the way, but it just references carbide cutting tips. I did a search on these, and there like 20 different styles. Does anyone have a recommendation on which one I use? Post a pic if you can. Or a link to where i can get it online.

 

I used sanding drums when I did mine.

 

didn't that take a very long time. The thread says carbide bits. i know those cut through metal pretty decent.

 

I think the reason lots of DIY guys try not to use carbide bits is because they are very aggressive and you could really mess something up if you slip just a little.

I may try this method for porting a tpi intake.

-Ported 89 TPI base, just about done (pics) - Corvette Forum

 

I have a die grinder with carbide bits. I found I could do a better job with a set of sanding drums. It went faster than you would think and I had better control.

 

They have aluminum oxide grinding stones that cut through cast iron pretty well and its easier to control. I was able to grind a port within an hour with this method and it came out very smooth.