I have an 87 SS that i upgraded to a 355 and wondering if the stock radiator will still do the job or if i need to upgrade and if so what should i put in?

 

The stock radiator should do the job just fine. If you want to upgrade a few options are a aftermarket aluminum radiator or you can get one for a. 80"s G body that came with a 5.7 diesel as they were factory 3 core radiators stock . Good luck