Not that I am aware of. All the pistons I have ever taken out in frame had to go out the top. The only way you could do that is if you pull the entire engine out and took the crankshaft out and then the pistons would come out, but I dont know how you would compress the rings and get them back in??
The crankshaft in the 504 engines is huge and you will not get past the crankshaft.
What is the problem with taking the heads off and pushing them out the top???
Molines: ZAU, M-5 Gas, M-5 cummins project, G-950, G-955 cab, G-1050, G-1050 green badged as a 2055 Oliver, G1355
Olivers: 1655, 1655 cummins, 1750 diesel, 1850 4x4, 1850 cummins, 1855 cummins, 2150 4x4 cummins.