I have a '94 Van with a 4.9. I put in a $42.00 K&N filter (only) in it, and it didn't do squat. If you're going to tow with it, you should consider a trans. cooler for the AOD.
Try
http://www.ford-trucks.com and go to the forum that fits your vehicle. There are a lot of folks there with the 4.9 that could shed some light on your request.
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'89 LX 5.0 - 5 speed. Original Owner
'94 E-150 Conversion Van