Re: [Chrysler300] Motor

["Ryan Hill" <ryan_hillc300@xxxx>]

With regards to the machining of the block, you should be able to take that 
block to at least 70 or 80 thousands overbore but I'm not sure what you will 
require? In any case it is good practice to use a torque plate when doing 
the boring.....especially when you are reducing the wall thickness 
dramatically. Also, when assembling the short-block be sure and use a rope 
seal around the rear crank journal(rear seal). They last much longer than 
the cheap seals provided in most gasket kits.

As for the heads, if you have access to a die grinder you can port match the 
intake to the head very easily and improve the flow quite a bit. Here's a 
trick:

When you remove the intake from the head, remove the valley pan and clean 
off the pan and the head mating surfaces. Lay the valley pan back in place 
and bolt it down if needed to center it. Inside the openings on the pan you 
will likely see quite a bit of head material that doesn't match the port 
pattern of the gasket.......spray some grey primer,white paint, etc. at the 
gasket on all the ports. When you remove the gasket you will have a perfect 
pattern painted around each port. With a die grinder, remove the material 
that is painted to give you a perfect "port match". Be carefull to grind at 
a 90 degree(+/-) angle from the machined surface and don't damage the mating 
surface.

In addition to removing the excess material from the lip of the port you 
should also smooth out any slag or burrs inside the runner that may cause 
extreme turbulence. Do not smooth out the runners too much as there should 
be some roughness to the runners to properly mix the Air/Fuel as it heads to 
the cylinders.

Repeat the process with the same gasket to the intake manifold and you will 
improve the flow and equalize the volumes being delivered to the combustion 
chambers. This can also be done with the exhaust side. There are some power 
gains to be had here but at the very least the engine will run smoother.

If the engine has been machined before, check the deck height and be 
carefull about removing any more material from the block or head. You could 
end up increasing your compression ratio, having a problem mating the intake 
to the head, and in extreme cases cause rocker arm failure(even with 
hydraulic lifters). This problem can easily be solved with thicker head 
gaskets but it's always better to know before you assemble the engine.

Remember also that with any cam change and flow changes that your carb 
should be adjusted or modified to allow for the new demands.

Hope this helps. Ryan


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