I need some help with my '65 C10. In my very long process of bringing this truck back to life, I now have the new (rebuilt) 230 straight six in the truck. I have gone through the break-in process, done some troubleshooting and have been running the truck for several months. Here are the engine items which are not original: - cam - slightly more aggressive - hardened exhaust seats for unleaded fuel use - block is actually from a 250 All else is original stuff from the 230 and new or rebuilt. The one problem I cannot seem to solve is an irritating "stumble" I get when accelerating. This is not noticeable at high speeds, mostly just when starting out. Or if I am at idle and hit the pedal, there is a hesitation before the engine "kicks in." I have two original carbs and rebuilt them both - no change. I have checked and re-checked the timing and am pretty confident that it is correct. PCV valve is operating correctly. All things seem to point to the accelerator pump, but like I said, I've rebuilt two carbs and it hasn't helped. I will point out that the pumps in the new carb kits appear to be of very low quality compared to the original ones. Could this be a problem with the vacuum advance? Anyone know an easy way to test this? Any other ideas about what might be causing this problem? Thanks for any suggestions!!
