Porting a log head

[Anonymous]

I have a question about porting a D5 log head: On the exhaust side, does the exhaust port get gasket matched? It looks like about an 1/8th inch of material is taken out. Then do I only clean the first inch of the exhaust ports?

My final idea is to fully port the head, to be best of my abilities, have 1.80/1.50 valves added 3 angle valve job and then modify the log to hold 2 5200 holleys.

Thanks, Ken

 

[CNC-Dude]

Im sure there are many who will argue the point of porting the log head at all, since most of the critical intake entry tracts are totally concealed, and would have to be accessed from the valve side of the head, and do a long reach up the port toward the carb to get to it! You would also have no way to know how consistently you were making the ports that far up,because you would have no way to gage it. You can focus on the bowl area in both the Int. and Ex. to capture some appreciable gains, and port matching the Ex. ports will have its benefits. As restrictive as those heads appear, im sure anything you do will help more than hurt....

 

[StrangeRanger]

Rather than a gasket match, simply match the ports in the head to the header/ex. manifold. You don't take away nearly as much material and run a much lower risk of cutting too deep and hitting the water jacket or of enlarging the port too much and killing exhaust velocity. Clean up the bowls, smooth the transitions and you're done. Polish what you can on the exhaust side. It can only help.

 

[Anonymous]

Thanks for the info. I am cutting up a head to get the material thickness, and see where the bumps are. I am also trying to figure out how to polish the inside of the log. I wonder if a flapper sand papaer and a long shaft will help. Any ideas?
Ken

 

[StrangeRanger]

You do not want to polish the inside of the log. On wet flow intakes you need a rough surface to keep the gasoline vapor in suspension. It's much more likely to puddle on a smooth surface.

 

[Anonymous]

No, just clean it up, remove flash any casting garbage.

 

[gb500]

ken - when you cut up the log head - it would be cool if you could post some pics of the sections

thanks
brett

 

[350kmileford]

Someone on here already cut up a log head and posted all the pictures. It was a few months back. If you found those it would probably make things a bit easier, no?

 

[Anonymous]

I have already posted pics: http://fordsix.com/forum/viewtopic.php?t=48073
Ken

 

[karfer67]

i remember reading about a type of porting where they push an abrasive paste through the head (mostly done on the intake side) to smooth out the ports. wonder if this would clean up a log head?

 

[CNC-Dude]

Extrude Hone! Possibly....