How do you size a mesh in a dropper script?

Hi guys you could help me with a tycoon problem, that is I have a script and I should put the mesh and everything is fine, only the mesh size is too big and I don't know how to do it, I tried everything I replaced also part.size and I put mesh.scale, but nothing! Help Please! This is the script:

wait(2)
workspace:WaitForChild("PartStorage")



meshDrop = true
--------------------
-- Mesh Settings: -- [If you want a mesh drop, set meshDrop to true up on top.]
-- Look at the mesh properties and change the inside of the quotes below to the appropriate
-- full link or the rbxasset:// style, doesnt matter which one you see in the mesh you want

meshID = "rbxassetid://3463051115"  
textureID = "rbxassetid://33533210"
--------------------


while true do
	wait(1.5) -- How long in between drops
	local part = Instance.new("Part",workspace.PartStorage)
	--part.BrickColor=script.Parent.Parent.Parent.DropColor.Value
	--part.Material=script.Parent.Parent.Parent.MaterialValue.Value
	local cash = Instance.new("IntValue",part)
	cash.Name = "Cash"
	cash.Value = 1 -- How much the drops are worth
	part.CFrame = script.Parent.Drop.CFrame - Vector3.new(0,5,0)
	part.FormFactor = "Custom"
	part.Size=Vector3.new(3, 2, 4) -- Size of the drops
	if meshDrop == true then
	local m = Instance.new("SpecialMesh",part)
	m.MeshId = meshID
	m.TextureId = textureID
	end
	part.TopSurface = "Smooth"
	part.BottomSurface = "Smooth"
	game.Debris:AddItem(part,20) -- How long until the drops expire
end