I think all the investment mods I was thinking would either make it more susceptible to crush or not survive burn out. How much heat can PLA take before it goes South? K
I reduced my bore to 1.25" rather than 1.33" which is 1/3 of the 4"- 350 bore. When I started boring the firedeck to accept the wet sleeves I afraid of breakout between adjacent cylinders so I held back on that dimension. Then when I started machining the cast iron sleeves I was concerned about the wall thickness and was not able to make up the difference so ended up with the reduced bore. As they say "don't hurt the runnin of it none". The fact that you are modeling a 400 cu in. with siamesed clyinders doesn't change your crankshaft journal locations so if you can reduce the bore at the firedeck enough to allow for machining it might work. You will need the same amount of material between the water jacket and the crankcase to machine the seat for the cylinder. Your marking of the head for a coolant passage is similar to what is done with the Challenger OHV heads that were copies of mine. the cast iron head in the crankshaft thread has a full water jacket which was created by a core as shown in the first photo.
