I am also searching for a replacement set of correct 3877203 hood springs for my '69 Z28 with cowl hood. My original 203 springs are weak and will not hold up the hood. In March 2023 I purchased a "correct spec" pair of hood springs from HBC, item #BDY-1516 which were OER brand springs. They worked fair but still allowed the hood to droop down about 4-5" from full up against the hood stop build into the hood hinges.
Recently, with the hood up and the car idling, the hood slammed shut. NOT a good or safe thing! If I pull the hood down about a 1/3 of the way, the hood will fall and slam shut. This could be a liability at a car show with your hood open and someone's head or hands are in the way! Until I can find replacement spec springs with the proper tension, I wrap a strip of Velcro around the hood hinge to make sure the hood stays open. This looks a bit better than an cut off broom handle used as a hood prop...lol.
I may try sand blasting my hood springs. This will input some compressive stress in the surface material of the spring which may help improve the tension in the spring. As long as you do not get the spring hot and stress relieve (anneal) and "soften" the material, sand blasting the springs should be okay to test. Its a cheap method to test but I do not have much confidence this will work.
If anyone find a set of springs that work well, please share your source, brand, and item number. There may be the same spec (size, no of coils, etc.) as the 3877203 springs under a different part number used on another GM model car but I have not yet found one.
Thanks,
Dave
