Springs are measured in pounds per inch of compression (or tension). If you have a bathroom scale and some weights to put on top, compress it till you get an inch of length change. You'll need to keep the weights from falling off, though. You might be able to just compress the spring by hand and read the scale on the fly. There are tools to measure valve spring compression, but they're kind of pricey.

[on edit] Here's a listing from the 1929-1954 Master Parts Catalog for the radiator support springs. It has some dimensions that might help. They sold for the princely sum of 13 cents each in 1954.
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Last edited by klhansen; 08/22/2024 12:24 AM.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.