LS3 and T56 install into 69C10 Shortbed: Need some help with info

[69_Chevy_C10]

Hello all: I have a question that I am hoping someone out there can help with. Long story short: I changed my project build from an old school 383/TH350 install.
I am wanting to install a T56 trans on an LS3 into my 69C10 shortbed. The kicker is that I have a Porterbuilt Inner Frame Stiffener installed. I have tried for the last 3 days to get some info from Porterbuilt but so far have been unsuccessful.

I know that I can adjust the Inner Frame Stiffener back slightly. There are several pre-drilled holes for adjustments. Also adjustable LS motor mounts allow for about 2 inches of forward travel as well.

Does anyone out there know of any clearance issues with the Porterbuilt Inner Frame Stiffener and the LS3/T56 combo? If you know of any success stories please let me know. Thanks all for the feedback.