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Do not have my heads off so hoping someone has measured this before. What is the depth of the dish on the 5.3l pistons in a LM7 ? trying to guesstimate difference in PTV clearance between the flat top and the dished.
looks like the dish on the aluminium is recessed .071" and diameter of 3.992" while the hyper-eutectic pistons are recessed .068" and diameter of 3.050"
the hyper-eutectic says "truck engine" so I am assuming that is the lm7 that comes in the trucks.
and based on these dimensions we can get close to what the CC of the dish is. So we need to figure out the volume of the cylinder (the dish).
the volume is calculated by V = pie * radius ^2 * height. so we have V = 3.14xxx * 1.525"^2 * .068" = .5" and .5" / .061024 = 8.19CC.
so here we have a dish volume of 8.19cc's - this is assuming the walls of the dish are 90 degree cuts . from pictures this does not seem to be the case so assuming some slight slope this will decrease the volume assuming the diamater above is from the top of the piston/dish. we can see that the 8cc's claimed by persons is most likely the correct dish volume . I have seen several people claiming the dish's on these pistons are only 2cc. from this , assuming I am not doing this wrong , we can see that the dish are closer to 8cc.
PLEASE, let me know if this incorrect or I am doing something wrong...
also after doing some google image searching for these dished pistons I saw several images where someone had cut valve reliefs. all of these cuts cut into the dish AND the outside of the piston dish that has no relief. so as far as PTV goes, if it doesn't clear the flat top pistons (4.8l) it will not clear the 5.3l as the dish only covers part of the piston - in other words, the dish does not increase PTV clearance . well as far as I can tell..
The chart you posted, the top piston is a 5.3, the bottom piston is a 6.0, LQ4 piston.
This is not correct in many ways. The lq4 is a 6.0 liter 364ci 4" bore . the chart I posted was for 323ci 5.3l 3.78" bore block pistons. Here is the chart for the lq4 pistons. based on this chart the lq4 pistons have close to a 6cc dish. the volume of the dish (assuming 90 degree cut ) is 6.06cc so its right around 6cc.
I believe the 3.992" is merely a typo and should be 2.992" . If you assume this typo and do the math you get exactly the same dish volume as the other piston - leading one to believe that the 2.992" is correct dimension and the 3.992" is merely a typo.
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What is depth of 5.3l dish from lm7? 
