Small Engines (Lawn Mowers, etc.): MTD Cutting Height, spindle, tire size

Question
I'm running a MTD circa 1999 Model #13aq670g372 Serial # 1e269c30008   I am installing a stock MTD 46" deck, formally a 42" deck. I fitted the 46" deck with 918-0430B spindles and the max cutting height I can achieve through adjustments is 2.25".
Would like at least 3" if possible. Deck fits and operated fine. At present the deck almost touches deck feed pulley in disengage so I cant see getting much more there. I'm down to spindle depth or tire size. Running 20X8 rear and 15X8 front. BTW blades rest 1/8 to 1/14 from bottom of deck. Does a shorter spindle exist?

Answer
42 inch spindle part number 618-0142.

This like provides various MTD spindle assemblies.

http://www.mowtownusa.com/133.html

I see several different spindle heights.  Usually the blades sit about half way up the deck...sounds like yours are close the to bottom of the deck.

Eric