I just finished what i believe is probably the easiest swap to convert at least an AD truck to disc. The patient was a 56 4400 34" Frame , the donor was a mid 80s P30 motorhome chassis with IFS.
I'll second Griggs request for photos and a new thread to show what you've done.
But I'll also ask some questions here.
A '56 is a Task Force (TF) truck, not an Advance Design (AD). Is the year a typo or is your project a TF? Your description of the frame sounds much more like a TF than an AD.
Are you driving this truck on the road already? I'd like to hear some description of how it drives.
Did you consider moving the upper a-arm bracket rather than modify the frame? On a pickup IFS that bracket will unbolt and the the holes could be redrilled to put the bracket against the frame. Yes that would change the alignment, but it should be possible with shims to correct the relatively small change it would amount to.
Please post more information and some pictures!
