A while back there was a thread on Autolite Inline carburetors, and I was very surprised to see that Kelly Coffield was offering parts and rebuild services for these carbs. I had no idea that anyone was doing this; I figured that the carbs were dead ended, with no hope of ever getting parts for them and making them tunable. As mentioned in that thread, back in the early 1980s I ran a set of those carbs on a home made individual runner manifold, on a 494" 385 series engine that I was running in my Mercury Cyclone at the time. I did not have good luck with the carbs, but I was pretty inexperienced back then and in hindsight figured that I just didn't know how to make them work. The two carbs that I ran were eventually sold to a good friend of mine to fund college tuition, and he had them all these years.
My friend had also acquired a second set of those carbs, and run them with his own design IR intake on a 385 series engine. He didn't have great luck with them either, and he was a pretty experienced hot rodder, but he did have better luck than I did. He's in his 80s now, and was looking to start selling some stuff. After the thread on this forum, and talking to Kelly, I got together with him and made a deal for all four of the carbs.
My wife has family in Iowa and I get down there fairly frequently, so it wasn't a big deal for me to get to Kelly's place, show him the carbs, and talk about the best way to proceed with them. They all needed a fair amount of work. The set I originally owned had been cannibalized for parts to use on the other set, and the other set had been drilled and tapped for attachment points for velocity stacks, plus the vents had been tapped to put a screw in fuel filter (of all things) on top of the vent, to prevent fuel from sloshing out of the vent during acceleration. There were also other cracks and defects in both carbs. I dropped them off with Kelly for disassembly and his analysis of what the four carbs needed.
The two carbs that I used to have had been polished at one point, and they cleaned up pretty easily, but the other two carbs needed a lot of time to get cleaned up properly. Also on disassembly of the four carbs, several of the screws that held the butterflies to shafts broke off, leaving the ends of the screws stuck in the shafts. Since the shafts have to be dead straight, heating them to get the screws out is not a great option. Discussions with Kelly revealed that he had designed and built what he called a "Big Shot" accelerator pump lever, to increase the accelerator pump volume; the accelerator pump issue was one that I'd had trouble with on my first go around with these carbs. Kelly had prints for the throttle shafts and the pump levers, so he sent those to me and I took a couple days to machine some new throttle shafts and pump levers for these carbs. The throttle shafts were tricky because as soon as you put a deep cut into hardened steel you create a stress riser that makes the shaft want to bend. However I had dealt with this issue before, with the throttle shafts on the IR intake setup for my FE Power cylinder head package, and so was able to straighten the shafts after machining. When finished I sent the shafts and pump levers down to Kelly for assembly.
In the meantime Kelly had been doing some welding on the carbs, to fix the cracks and ground out areas, and also to fill in the tapped holes that had been used for attaching the velocity stacks and fuel filters. When that was all finished and welds cleaned up, he also glass beaded the two carbs that needed the welding, to provide a nice uniform satin finish. He reassembled the carbs with a bunch of new parts, including floats, needle and seats, accelerator pump check valves, jets, etc. He also put new tags on three of the four carbs, because they had been missing.
The pictures below show the finished carbs. I was very pleased with the results, and have plans to run a pair on a tunnel port engine (after I design an intake and get it cast), and also a pair on an SOHC, where I will have to fabricate an intake. Just from an eye candy perspective they are very cool, and I am hoping that I can get them to run reasonably well on a nice street engine. We will see...
