I have a problem with the Goodwrench 350 that is in my 68 ragtop. I recently rebuilt the carb, carefully and using a book, so all new seals, needles, seats, etc. I also replaced the fuel pump, an Autozone no name with a Carter mechanical about the same time. I now have a problem where whenever the car is warmed up and cruising (partial throttle), if I hit a medium sized bump, the engine will bog down right after hitting the bump. Depressing the accelerator further does nothing, it acts as if I cut the ignition. If I let off the throttle completely, it will usually backfire through the exhaust and then I can resume driving as normal. My best guess now is that when I hit a bump, the floats in the carb are dropping, and the (possibly) too high pressure of the Carter pump is causing gas to rush into the carb faster than it should, and overflow into the engine. Thus I'm thinking I should install a fuel pressure regulator, but I'm not having any problems at other times - it seems most people with too high fuel pressure have problems with the engine running too rich all the time. I was hoping maybe someone could suggest something else to check. I had some problems with it behaving similarly occasionally when cruising down the highway (even without hitting bumps), but that seems to have been fixed by changing from R44TS plugs to R45TS. What plugs should I be running in this engine? It's stock from the crate.
Thanks for any help.