Are you interested in money, or satisfaction? The answer depends on that. There seems to be very little demand for a correct 307 restoration. The cost to restore would not be significantly cheaper than an SS. I doubt the resale value would come close, all other options being equal. If you you want to preserve it there may be personal satisfaction from the restoration. Either way, I have become a fan of a digital camera, and documenting the way it was (right or wrong) as you go through the process.
My Camaro is a 307 powerglide that almost went to the scrap yard. It's not a highly sought after car, but it is mine. I am not keeping it stock, however I am keeping what is left of the stock parts, so that it could be easily returned to at least the way I got it if desired. The most significant changes are the TPI fuel injection form an 87 Trans Am, and I will be replacing the trans with something newer. Mine is not for sale, but I can not justify an expensive restoration either. When it does get back on the road, it may become my daily driver, so that also affects what gets done with it.