which dremel bit is best for porting headers.

For working with a soft metal like Aluminum, you can use a "High Speed Steel" cutter. If you were talking about cutting steel tho, you'd need a Carbide bit, just for future info. Your header is Alum. as you prob. already know...

yea i know im plannin on porting my ths header what about this one.http://www2.towerhobbies.com/cgi-bin...?&I=LXC563&P=7 http://www2.towerhobbies.com/cgi-bin...?&I=LXC562&P=7 which is better to use. but when porting.my goal is to get the opening bigger right. do i make it like a funnel shape

Guess you answered my other question from the other forum. Saw that old cast manifold and thought that was what you were talking about. W/ the THS header, you just want to match the port. Take the header, and a magic marker, and color the face of the mounting flange. Then take the gasket and use it as a template to scribe inside the exh. opening w/ a sharp awl or ice pic or something. Now, just match the headers opening w/ the gaskets and you'll get it just about perfect w/ the exh. stack on the engine. You want a smaller bit than the one you linked to. You basically want to open the ends of the passage, and sort of "funnel" the exh. gasses into the header. A 1/8 or 3/16" dia. would be better, and be real careful of going too deep in, 'cuz it's real easy to go right thru the thin tube part of the header! Just grind into the thick, flange part in other words, then blend into the tube...

ok got it.. so take a spare gasket and cut it to the shape opening of the engines exhaust then color and stamp the gasket onto the header.ok good ima practice on the cast header.

Coloring the gasket might work too, but I was saying to color the alum. header flange, then scribe inside the gasket opening to give you the size...

oh... put the gasket over the header then color the opening of the gasket. then juss dremel the colored part.

That might work O.K. too, but actually, I mean to use a dark, contrasting color, like black or blue, red, and color the entire flange area. Then take the gasket and line it up w/ the bolt holes, and take the point of an X-Acto knife, or a sharpened nail, and scratch thru the color tp leave a shiny "scribed" line for you to follow along inside of...Machinists typically do this proceedure w/ a substance called Dykem Blue, it's a liquid in a bottle, w/ a brush - swab in the cap. It just gives you a contrast so you can see what you're doing better.

oh lol sorry for the trouble. ok i got it now.