Why Cant You Use It? Most People Are Using 2x2 Angle.... I Used 4x4, But Its Just Extra Weight... The Only Reason I Went With The 4x4, Is Because I Ran My Rails At The Angle Of The Pump Shaft... That Way I Didnt Have To Angle My Blocks & Motor Plates... I Run A Linco Drive Line So My D-shaft Has To Be Dead Nuts Straight... I Know Some People Dont Think U-joint D-shafts Should Be Straight, But Thats How I Do Them To... The Next Time I Do A Rail Kit I Think I Will Run The Rails Leval And Go The Full Length Of The Boat To Tie In The Pump Braces, Seat, Pedal Assembly, Fuel Tank, Ect... Any How, 2x2 Is Perfect, But What You Have Will Work Fine To... Every Time I Look At Mine, I Wonder Why I Went With 4x4... I Used 4x4 In My Challenger Too, And I Ended Up Having To Cut A Crazy Notch In One Of The Rails, So I Could Install A Standard Size Starter If The Small One Ever Went Out... Cant Always Find A Small Starter In A Pinch... If You Want More Bite On The Stringers, Rip It Down To 4x2 And Use The 4x Against The Stringer.. The Outside Of Your Blocks And Motor Plates Should Run To The Inside Edge Of Your Stringers... Less Leverage On The Stringers, And 2 Inches Should Be The Perfect Rail Width For Your Mounting Blocks.... Nelson#109