Hi everyone, my first time doing valve springs. The engine is the rebuilt (by the previous owner) 318 that I was told is from an 80's Ramcharger. He used a Summit K6900 cam but left the stock springs. I thought that the bad cutting out when it hit about 4000 rpm was a fuel problem, since it still had a 2bbl on it, but after changing to a 4bbl I've now concluded it's valve float since I can duplicate it with the trans in Park by slowing increasing the throttle. I ordered a set of TrickFlow TFS-16901-16 springs and the matching TFS-514000423 retainers from Summit. I've gotten as far as taking one spring off and noticed there's a shim under it. My first question is, do I reuse that shim with the new springs? I'm guessing no, but thought I should check. Second question, which is the real problem... When I put the springs in my "cart", I also added the retainers that Summit said were required. I just found out when struggling to get the keepers to fit that they are for use with 0.342" valve stems: I measured the valve stem and it's 3/8". Does anyone know if the Comp Cams 740-16 retainers will work with the TrickFlow springs? The application tab says they cover a wider range of valve stem diameters: COMP Cams Steel Valve Spring Retainers 740-16 I just tried calling Summit but they don't have weekend tech support, so hopefully some here can set me straight.