I have had a 161" wheel base 48 Chevy 6400 on our 18' flat trailer several times, the front fits just fine, and the rear tires stay behind the trailer fenders, so even though they are to wide to fit between it makes no difference, as they don't have to.
I can dig up a picture if it would help any?

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-