Steve's got it covered.

The front one stays because it ties the frame and front springs together as well as holds up the radiator and fenders.

The one at the bellhousing is similarly important to tie the frame together at the back ends of the front springs.
Don't remove it unless you have something else to do the same job.

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-