Well, it�s been a while - time for a summary/update. In deciding between a 2bbl and 4bbl, I came across an inexpensive, slightly damaged Rochester 4-jet (4GC). This carb hadn�t been on my radar, but I had one back in the day on a small V-8 and liked it, so thought, let�s give it a try. Long story short, I went through numerous times of disassembling and reassembling while I relearned carb rebuilding (it�s really a pretty simple carb) and chased down some fuel leaks. Meanwhile, I came across a manual choke version of the carb (4G) that still had the original id tag(!). The tag id�d the carb as period-correct for my truck - very exciting! So, rebuilt that carb and got the truck back on the road.
So far, the pros: truck starts much more easily when cold and part-throttle response is better than with the prior 2-jet. Cons: seat-of-the-pants power seems reduced (maybe not a big surprise given the smaller throttle bores) but MPG after the initial half-tank run was a little less than 13 MPG, about the same as with the 2-jet. I was hoping for at least 14 and wishing for 15. The spark plugs look pretty decent so far, so I think the jetting is about where it should be. I�ll keep driving as it is for now and see how things settle in over the longer run. Happy to answer any questions about the project and hear any further suggestions/advice.
