If you're not up to doing a V8 swap yourself and aren't really excited by that idea anyhow...keep it simple, more or less original, and stick with the Inline 6.
Now would be the time to look for that 261 you may have also thought of.

•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-