Intake air tube size?

Heres more on what i have done...
Pulled engine back out, welded in box 100% all around... welded in 16ga angle to frame rails where i cut off pinch weld... and cut in an opening for the air intake... my hand can fit in intake hole, so i think ill have enough air for my 4" intake tube.... im also going to build a sleeve and weld it from radiator support to air box for smooth air flow.... and ill aslo build a detatchable air defuser (so i can change parking light) behind massive intake hole, to keep water and road debris off filter....
2mrw ill try to finish up the air box

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