9", why bother?
Leave it as it is and you have a tad more room in an already small bed.
Turning radius is good to start with, so no worries about the slightly longer wheelbase, you won't gain all that much by shortening.

What's the "reason" you want to shorten the frame?

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-