3000 Ford Diesel with different size pistons

[martind28]

Last Wednesday my 69 Ford 3000 with 4961 hours started blowing oil out exhaust and down exhaust manifold. Removed head and discovered engine had been sleeved and had pistons stamped D on #1 and B and #2 and #3. Anyone seen this before and are those pistons still available?

 

[TractorTech]

Someone mayhave just used what they had on hand. Pistons are available at New Holland dealerships.