head porting question

[art25]

Hi guys,
Ive been getting rolling on the motor everyone helped me get ideas for in the thread "79, 360 cam selection" and i've started porting the heads. i'm using a standard dremel and the exhaust bowl came out awesome. The intake though has a hump of material running way down the tube that i cant reach with the dremel to really knock it down. also where it comes to an end around the pushrod guide it forms a deep valley on either side of the guide. So my questions basically are, how do i get in there to cut down that hump,? is there long dremel bits and stones somewhere? Do i have to knock down that ridge and if so how much? and finally how should i shape the bowl where the valleys are formed? Thanks!

 

[moper]

If you're just starting, I wouldnt do any more than blending the area about 1/8" below the valve seat angle down into the bowl. Bigger is not better, and with limited equipment and experience, you can screw up a lot more than help by grinding too much in the bowl area.

 

[bad440]

If you're just starting, I wouldnt do any more than blending the area about 1/8" below the valve seat angle down into the bowl. Bigger is not better, and with limited equipment and experience, you can screw up a lot more than help by grinding too much in the bowl area.

x2 just blend dont go bigger.

 

[rumblefish360]

Art, that area is best left to a machine shop with deep reaching tools. Those valleys on each side of the guide is something you really need a long shaft bit and they do not come in a small dremel size. Just a larger size that you would find on a die grinder.

What some shops do is ethier whittle away until thedesired shape is found or they have the head in a stand/jig held down under a drill press. A bit is in the drill of the press and moved downwards cutting away the top of the guide and the boss around it until the desired height is achieved and then the die grinder is used to finish it off.

Shop work. Not many can do this at home. It can also be dangerous at home if things are not set up right. It aint preety seeing a heavy iron head flung across the garage floor.

 

[art25]

Thanks guys, a little blend work it is! This proves the point its good to ask questions before going too far.

 

[TurdFerguson]

You will need a long shank carbide bit and larger chuck grinder.

Remove the kink, it will increase the flow and rid some turbulence on the roof, with blending the seat too, you could pick up about 25 cfm and be in the 235-240's range.

grind out the roof hump/kink profile the last 1/2 of the guide and blend the bowls-done.

You would be doing wrong if you opened the pinch up at this level, so don't worry...you are good.