(Words and photos by Scott Liggett) – We need to apologize for our lack of updates on my Project Hay Hauler, the 1967 GMC pickup. When we last checked in on the truck, I had just installed a BluePrint Engine’s 355 crate engine and a New Process A833OD four speed overdrive to replace the old granny low SM420 4 speed that was original to the truck.
Going back a bit here, I reused the headers that came on the truck, but I did have them sandblasted and painted to pretty them up. The lower half of the headers were pretty darn rusty, so I was pretty sure the rust would return in time. I had plans to replace the exhaust last summer, but I didn’t make it that far.
At that time, I just reconnected the old crusty exhaust with store bought flex pipe pieces in hopes it would last me through last winter. My plan was to save up for a new exhaust last summer. That plan didn’t quite work out as planned.
On a beautiful March day, I was hot rodding around after work and heard a different tone from the engine that wasn’t the good kind. After getting back home, I got out to listen to the engine under the hood, which it still sounded fine. I then walked around the back of the truck and noticed the left side exhaust sounded funny compared to the right side. I put my hand over the tail pipe of the left side exhaust and barely any exhaust was coming out. OK, that’s weird.
I crawled under the truck and saw that the tailpipe had rusted through and was cracked.
I gave the tailpipe a bit of a kick and it broke off, spinning 90 degrees. One more swift kick and it fell to the ground. Problem solved. Or, so I thought.
The exhaust pipe and muffler were dangling by the collector bolts and my crappy flexpipe extension. Luckily the bracket was still there. A new nut and lock washer kept from falling off for two weeks until I got in with the local exhaust artist, Scott at Exhaust Pros here in Kearney.
In the meantime, I ordered up new mufflers and pretty new headers. The mufflers were Summit’s brand, stainless steel straight through design. I didn’t get the polished versions because this is a truck and I am not about to crawl under to keep mufflers polished. The headers are Flowtech Afterburners. They are for 73-87 Chevy trucks, but work on this ’67 GMC with a little frame trimming.
As you can see, the headers were already starting to rust again. The driver’s side had a hole right at the weld of the collector which was producing an annoying exhaust leak.
A comparison of the new to the old headers. I got these Flowtechs for two reasons. They were on the truck and fit. And second, they left plenty of room for the spark plugs on the engine. If any of you ever had headers that burnt plug wires, you know what I am talking about. They are a bit of a funky design with an extra long collector with three pipes going in the end and one hitting the collector halfway down its length. Not really sure what that is supposed to do for performance.
Replacing the headers on this truck was not a simple process. The starter and the entire clutch linkage had to come out, and obviously, the spark plugs and wires, dipstick tube. I also had to remove the motor mount bolts and tilt the engine side to side. The whole process took a couple of evenings after work. In the picture below, I kept the bags the headers were shipped in on them while I slid them up and into place from below. This helped keep them from getting scratched up during the install.
Here is the beauty shot after it was all put back together.
I had a few days before my exhaust shop appointment, so I reconnected the new headers to the old exhaust. I did install header reducers with a built in O2 sensor bung. You can buy these separate for about $25.00. I got these at Advance Auto Parts. They had them in stock.
Below is the after shots of the new exhaust. Exhaust on these old trucks is not a complicated matter. Lots of straight pipe until the rear axle.
Below is a short Youtube video I took the day I picked up the truck at the exhaust shop. It was windy and snowing, so I didn’t spend a lot time getting all artsy on it. I have to say those Summit mufflers were quieter at idle than I was expecting. It gets real throaty when I get into the big pedal.
One little issue I was having was the alternator belt. I could not get it tight enough to keep it from slipping. The valve cover was in the way to go to a shorter belt. My solution was a longer chrome upper bracket that allowed more lateral movement to tighten the belt, and stop the belt squealing. The first picture isn’t very good, but it shows the original upper bracket.
I didn’t mount the new bracket in the stock location, but in the front hole of the intake manifold. It worked really well, with the exception I have more chrome to clean now.
I decided I wanted a console. I really wanted a ’70’s Blazer console, but finding one of those in a salvage yard is near impossible. I went looking at other options. I found this console in a 1991 Ford F150. Heresy!! A Ford part in a GMC pickup. It was $10. Shut up. If so disgustingly filthy, the cup holders were half filled with smelly goo. Some kind of similar disgusting crap coating the bottom of the inside of the console. It was so dirty when I bought it, I thought it was black. But, as you can see after I cleaned it, it was actually dark gray. Close enough to match my truck’s interior.
I am planning other changes to the truck in the near future, but things got put on hold as the old 383 in my ’65 Impala started banging away with really ugly noises. I now need to keep the truck running until I solve that problem.
the 67-72’s with trailing arm rear suspension are harder to do exhaust on. the problem is the cross member for the trailing arms. someone made or still does a weld in plate to allow duals threw that cross member.
As for the A833OD the shifter boots & shifter knobs for those are sought after items. I sold a NOS shifter boot on eBay for $550 and it went to Saudi Arabia. I only paid $300 for the lot of NOS parts it and the $55 dollar shifter knob came from.
The most important thing here was that we get the psn codes free online from the generator which was really good for us.