Match Porting 6.5 Turbo Diesel Heads

The idea of match porting 6.5 turbo diesel heads and especially a full port and polish was always a very intimidating thing for me. Some heads have very thin walls that can be penetrated if you’re not very careful, then you have to either junk it or get it welded. Either way, I wasn’t in a position to take the chance. However, there are few things that can give you free power like porting. Free meaning usually you get power at the price of durability, mileage or both. 

So, when I got my 506 block Optimizer 6.5, I was ready to take the chance. I was only going for a match porting job this time so I didn’t feel there was much danger. Baby steps to success I always say and this keeps it at a difficulty level that most reasonably competent mechanics can handle.

And So We Begin

Here we are assuming two things;

  1. The heads have been removed from the engine or are new.
  2. You have already cleaned them if they have been removed from the engine.

Set them on your work bench so that the ports are facing you.

First, we’re going to create a mark to show the area to be ground away so with your sharpie, color all the way around each port. Color about ¼” or so out from the port edge. Once we get into the process, you will see what this is for and can add more color if necessary. 

Place the locating pins on the gasket in their corresponding holes in the head. Though it’s probably not necessary, I didn’t want to destroy the pins before final install so I only pushed them in slightly. 

Holding the gasket securely, scribe around the perimeter of the gasket of each port. Since there is some slop in the gasket even with the locating pins, you want to keep where you put the gasket as consistent as possible.

Remove the gasket. Now you can clearly see where you need to grind.

Fill all the open holes with rags. You want to keep as much shavings out of the head as possible and believe me, metal will fly. 


Make sure that there are no pieces of rag where your bit can touch and grab. You will twist it up in your bit instantly and likely bend your bit or break something. Like your fingers.

Start grinding away the excess material.  The idea is flow. So imagine air flowing in from your scribed line through the port and into the cylinder. Just ease the transition from your scribe mark in to the existing port wall. Take it very slow. Don’t go all the way to the line right away. When you get close to the line, put the gasket back up and take a look at your progress. Make a mental note as to where you still need to take material away and how much. Take a bit more metal away, check again. Check your progress often. 

When you have a good, smooth transition from the gasket in to the port, you’re done with the bulk of the porting. 


One more step

When I finished grinding my heads, the surface of the port was a bit irregular, but smooth. Probably smoother than the factory wall of the port and I was feeling the pressure of time so I left it at that. However, I should have followed through with the final step. Using a sanding drum on your Dremel, take some time to smooth the grinding that you have just done. Go ahead and smooth it as far as you can reach into the port as well. 

On a gasser, you wouldn’t want to put a mirror shine on the port walls because it can cause fuel to bead on the wall, so you want to leave it a bit rough to cause enough turbulence to keep the fuel atomized. In our 6.5s, we only have air being pushed through the intake ports so there is no fear of beading and can polish them to your hearts content. Make ‘em purdy!

Done! Now Clean ‘er up!

Tip the head forward to dump off as much metal as you can and hold it there while you pull the rags out, trying to keep as many shavings as possible out of the head. Get a good shop vac and suck the whole head clean. It should come pretty clean if the head was clean and dry to begin with. 

Good job, now you have added a way for your engine to breath better which will add power and add mileage. Along with the other [performance air mods]; better intake , turbo and exhaust, your 6.5 turbo diesel will get all the air that it could ever need to burn all the extra fuel that you want to give it for all that more power!


A Thorough Review Of The Dremel 4000 Rotary Tool


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