[jrmunn]

I didn't make any changes to the manifold. Seemed like I needed to rebuild the original carburetor (again), so it was a good time to try the Holley 500. I just bolted it over the adapter. Truck runs fine (better), just a little rich. I have smaller jets, but haven't installed them yet. Except for choke, conversion on my '64 305E was easier than a rebuild. The truck starts easier, which is good for the starter and battery, runs rough until it warms up (probably an adjustment issue), then runs better and with more power - especially at the top end. My main concern is potential to over rev the engine while trying to keep up with freeway traffic, which I have mostly solved with taller tires and 3.54 rear end - and trying to keep in mind that these trucks were not designed to go or stop as fast as modern vehicles. One thing to watch out for is that a backfire can pop off the vacuum port plug at the rear of the carburetor. This causes truck to die at idle and run only at higher rpms.

JRMunn