On these trucks all you'll ever need is the small set for 45° flare for the brakes, vacuum, and fuel.

If modifying things and for whatever reason decide to use some AN fittings you may have occasion to use 37° but could also avoid that situation if it came up.

I have the big set, not sure I've used the 37° dies yet... glad to have the ability should it come up though.

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-