it has to be more then .002 to make it leak . i can not say if you have a good machine shop there ? i only cut to a clean up but i have cut down many intakes to shorter deck engines .most of the time on set up there going to mill the intake off old intake angles thats ok . less heads of been rolled .i all ways used permatex aviation No2 on the dry part of the intake i do not care to draw down the intake dry . i use RTV only on intake rails and around water ports only.... not RTV and rubber gaskets .it one or the other and never use the rail gaskets