Looking for information on putting a 69mm crank in a 420/440

[125ccCrazy]

I called one of the distributors that sell the cranks, rods ect and asked them what would I need to do and what combination of rod and piston I would need to put the 69mm crank in a 440 block and the answer was "I dunno",,,Really??? you sell all these parts and race engines and dont know what needs to be done and purchased to make it work? so my next step was to post here to see if anyone has done this and what I would need to do... The cranks are a cheap purchase to gain another 20cc...

Any insight would be greatly appreciated

 

[FirePowerMinis]

Piston goes up 1.5mm more, so trimming the dish lip off the piston, or getting the VC one, is a good plan.
Rod usually hits the balance shaft. They don't seem to shake or break from a little kiss from the carbide.
Even cheaper on the 'Bay 69mm Stroker Crankshaft Crank Shaft For Gx340 Gx390 420cc 440cc Clones Engine | eBay