'm running a 1411 Edelbrock carb on a Edelbrock 2166 intake atop a Ford 460. The 460 is mounted in my 1982 Ford E350 based Class C Motorhome. I'm using the recommended 1483 and 1495 Edelbrock linkage adapters and everything drives a C6 automatic with GearVendors overdrive. The engine was professionally remanufactured about 8,000 miles ago and has a RV torque cam. The camshaft timing has been reset to 0 degrees and it runs rather well below 3.000 rpm. Above that it seems to run out of breath by 4,000 rpm. While checking details, I found that with the accelerator pedal fully depressed, I was not fully opening the carb throttle and it appeared that the mechanical secondaries were not opening! I moved the throttle cable connection at the 1483 linkage to the second available hole since the measured lever arm to the throttle shaft was shorter than the first of two holes I used and there was a small improvement. Now the secondaries are starting to open but far from completely! There appears to be no way to modify the length of the cable stroke on the E-series van. Is this a common problem? I'm about to drill more holes in the 1483 adapter. Are there any suggestions for other options or for the proper lever arm distance to use for this application with the 1483 adapter? Any help would be greatly appreciated. I'm attaching a diagram of the 1982 E350 throttle linkage for the 460 and a photo of the 1483 linkage adapter for better visualization of the problem. Any help greatly appreciated.