These pistons are BRAND NEW. They are for a 383 .030" over with a 19cc dish volume using a 3.75" stroke crank with 5.700" connecting rods. The reason for using a 5.700" rod over a longer rod is to keep the pin from needing a support rail. This allows the oil ring to do its job much more efficiently, keeping oil out of the combustion chamber. Especially in a power adder application where avoiding detonation is of most importance. These pistons were purchased for a build where 8.5:1 (blower/turbo) to 10:1 (nitrous) compression is desired depending on deck height and cylinder head chamber size (60cc-72cc). They have been smoothed, re-worked and polished to resist detonation with high cylinder pressures and the pin upgraded to a JE .180" wall 52100 pin. Pictures show before and after the work was done as well as the pin upgrade comparison. They will work with any type of power adder (I was going to spray 350+hp worth of nitrous with them for about 900-950hp total) or for any build where you want the best piston possible for the price. These are 2618 forged and retail for $625 a set. This is a very good deal. I have since changed the block I am using and need to use a flat top piston rendering these useless for my application. No rings included. If you have any other questions feel free to ask. Thanks for your interest.