420 = 40 series tires with a 20mm hub.. I changed to a 17mm hub because thats what all of my wheels are.
as for the truck body the 3905 emaxx body is close to the same length, the rear wheel well comes up a bit short but that dump truck has no rear wheel well so it should be fine, just the height adjustments me need some playing with
Thanks Jay, after doing some more searching the wheels I am digging are in the 17mm as well and I have some more options for bashing wheels as well. Seems like a more logical route. Ya I think I going to have to give that body a try.