ya looks like it might hit the other side of the manifold if i go from the top down, maybe thats just the way it looks

 

That is because it is not supposed to go all the way in. You drill and tap the manifold for the compression fitting, and install the fitting. After that you can stick the probe in the manifold so that the TIP of the probe is in the center of the manifold. They all stick up out of the manifold some.

 

you want the probe to be as far away from any castings to get the best reading

 

Castings? The manifold is a casting.

 

i mean the tip of the probe where you get the actual reading

 

Right. Hence, the tip should be in the center of the manifold. There are pics that show how to locate the probe in the manifold. Then you just insert the probe through the compression fitting until the tip is in the center of the manifold.

 

its all preference but most recommend drilling in the back part of the manifold because the back three cylinders run hottest. some more tips when drilling is placing grease all over the bit and around the hole, then run a pin magnet down in the manifold to get all the shavings out, failing to do this could ruin the turbo and the engine. here is a link to help out

http://www.piersdiesel.com/TechPyroInstall.htm

 

i pulled the turbo then drilled but the magnet and grease works i did the magnet and grease even though i pulled the turbo just to see how well it works dosnt get everything but once you start the truck the shavings blow out befor the turbo ever starts to turn anyway.