I have installed dozens of frame rivets in sizes up to 3/8" diameter.
This thread explains how I do it with the tools I have available. https://www.stovebolt.com/ubbthread...g&topic=0&Search=true#Post380215

There is a chance that the original ones are set cold with a huge press or cold riveting machine (anyone know for sure?). Unless you have one of those, and can take your frame to it, installing them hot is the way to go.
Check the link above.

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-