When we prepared our '79 Chevy Big 10 for Americruise, we knew there wasn't going to be enough time to take care of everything we wanted to do. Since we had only owned the truck for a short while, there were a lot of unknowns when it came to the truck's maintenance history.
The first thing we went after was the cooling system to make sure we had new belts, hoses, and antifreeze, followed by a thorough renewal of all the lubricants. One of the areas where the Big 10 didn't seem to need a lot of attention was its state of tune. Running around town at sea level in Southern California, the truck ran pretty well, with only a very slight occasional hesitation. Our opinion that the Big 10 ran good enough was further reinforced when we installed a Magnaflow catalytic converter, went to one of California's state-approved test-only centers, and passed the smog test without a problem.
With our concerns about the 350-inch Chevy put to rest, we left for Americruise with our sights set on a first night destination of Grants, New Mexico. Leaving early in the morning before traffic, the climb out of Orange County at 70 mph takes one from just a few feet above sea level to a 3,811-foot summit at Cajon Pass in about an hour's time. The rapid ascent up Cajon didn't present any real problem for the Big 10, but adhering to our newly adopted policy to try and break the truck as close to home as possible netted only 80 mph up the grade with the gas pedal glued to the floor. Once we hit the high desert's plateau, the truck was happy cruising between 75 and 80 mph, turning around 2,000 rpm and getting not bad gas mileage doing it.
All went well for many miles until heading east out of Kingman, Arizona. On a long climb passing slower traffic, we were starting to discover the 350 had a dark side lurking when it dropped from third into second passing gear. At full throttle the revs shot up for a second or two, followed immediately by the engine falling flat like it had just been shut off. It would then turn back on when the revs had dropped below 3,000 rpm. On flat stretches of highway, the truck was still more than capable of getting a speeding ticket, so we just cruised around the 75-mph speed limit and made sure not to kick the tranny down into second passing gear when we needed to get around slower traffic.
It wasn't until we pulled into Denver on the return trip home that the 350 showed any more signs of a problem. As expected based on past experiences driving a carbureted motor through Denver, the city's high altitude really had our engine running out of breath. We stopped for a while to visit with Todd Gold at Gennie Shifter and then tour one of the most amazing collections of old auto parts at his Vintage Auto Parts location in the heart of downtown Denver.
The first step was to remove...
The first step was to remove the Delco-Remy HEI's distributor cap and spark plug wires, being very careful to note the position of the No. 1 spark plug on the distributor cap.
Next, we matched up the No....
Next, we matched up the No. 1 spark plug terminal from the HEI cap to the new Performance Distributors DUI cap. Failure to do this step properly can result in having to re-establish the engine's initial timing.
We found the best way to swap...
We found the best way to swap in the new DUI distributor was to position the Delco-Remy distributor with the rotor pointing to a mark on the firewall.