threaded freeze plugs(core plugs)???

[fox3streetracer]

i am building currently a 410w with a machined 74 block.the boring has already been done,was going to get threded freeze plugs installed,but only 1 machineist here can do it,and he said it might put more stress on the block and i should have done it before boring.is this true?will they help block rigidity at all?

 

[Daggar]

i am building currently a 410w with a machined 74 block.the boring has already been done,was going to get threded freeze plugs installed,but only 1 machineist here can do it,and he said it might put more stress on the block and i should have done it before boring.is this true? Yes will they help block rigidity at all? No