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How to Tune-Up a Small-Block Chevy, Part One

Revamping the ignition with the help of Duralast, Autozone & Pertronix

Jun 4, 2020
Read More on This 1964 "GMC"
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Installing Cragars and Skinny Whitewalls on our 1964 "GMC"

If you've been following along, you've seen that during our recent "downtime" we've taken the opportunity to get our 1964 "GMC" back on the road. To be fair, it has quite literally always run. When we bartered for it almost 20 years ago and found it in the back of a subpar body shop covered in Bondo, all it took was a battery and it fired right up. When we were first building it way back in the day at Totally Polished, it was torn down to a cab on a frame with an engine and the radiator only being held up by the radiator hoses, but it never failed to move under its own power. After several stints of sitting for a year or more, we've always been able to throw a battery in it and head to a show. The truck has been to Paso Robles, Phoenix, San Diego, and everywhere in between. It has never sat on the side of the road, and it hasn't been on a trailer for 18 years.

Somehow, through all of this, we have never given the stock(ish) 327-c.i. small block a proper tune up. In fact, we've never touched the actual engine at all—ever. Sure, we shaved the firewall, added an aluminum radiator, brake system, airbag suspension, even swapped the front-end sheet metal, and basically built up every single component around it, but nonetheless, the engine remained untouched. Recently, this began to come to light when we cleaned up the brakes, added new Cragars and Diamondback Classic skinny whitewalls, then installed our custom tube Glory Grille, all right before hitting a couple of the recent Quarantine cruises our buddy Jason and friends puts on in Huntington Beach. Once again, we hit the road without giving a thought to the old 327, but this time it started to let us know it was tired of the poor working conditions. The occasional chug or pop and general lack of power was apparent.

We decided to do a simple tune-up and wanted to cover most of the basics before the next cruise, starting with the ignition system, as some of the basics of engine maintenance seem to be becoming a lost art. This was not about bolting on shiny or high horsepower parts on and hoping for the best. We could have done that years ago. This is about getting the correct replacement parts on the engine and tuning it to stock specs. Check out our process below, and check back soon because we also address our cooling system and even take a look at the transmission before we call our tune-up complete!

Photo 2/25   |   Over the nearly 20 years we've had our '64 C10, we've purposely never tried to paint or dress up the engine. Something about the fact that this engine (with a few mods) rolled out of the factory in this truck, and doesn't look to have ever been removed, makes us happy. And the period-correct Edelbrock intake manifold and Holley carb are pretty awesome, too. But after years of neglect, the engine let us now it was ready for some attention.
Photo 3/25   |   We contacted our friends at the Autozone in Hawthorne, California, for a pretty thorough list of ignition replacement parts. Included are Duralast plug wires and a points set, AC Delco plugs, and an Accel distributor and rotor cap.
Photo 4/25   |   Jumping right in, we pulled the old plug wires. We knew our distributor was in the correct place with the No. 1 plug wire roughly pointing to the rear bolt on the valve cover. If you're not sure, you can pull the No. 1 plug (front driver's side) and turn the engine over with a rachet on the crank pulley bolt until air blows out the hole, indicating that the piston is at top dead center. When you pull the cap, the rotor will be facing the number one terminal on the cap.
Photo 5/25   |   Next to be removed were the plugs. It is crazy that we hadn't at least replaced the plugs, but we cannot tell a lie; it never happened.
Photo 6/25   |   Check out this comparison shot of the new and old R44T Delco plugs. We were stunned that the old ones were even firing!
Photo 7/25   |   We promptly got the new plugs installed and moved back up to the top of the engine.
Photo 8/25   |   To remove the distributor cap, what look like bolts are actually spring-loaded clips that swing off the bottom of the distributor.
Photo 9/25   |   The cap, along with the crusty plug wires, were removed and tossed.
Photo 10/25   |   Two Phillips screws hold the rotor in place. It was removed next.
Photo 11/25   |   Next, the points and condenser were removed. The wire lead was removed, then two screws are loosened to slide the points out. The condenser is hiding on the other side of the centrifugal advance weights and is held in by one screw.
Photo 12/25   |   It's hard to see, but the contact area of the points is supposed to be flat and shiny, not chalky and crusty. Again, it was a minor miracle that the truck started and ran!
Photo 13/25   |   These days, the points and condenser come as a combined unit, which makes installation easier, but gapping the points very difficult.
Photo 14/25   |   With the pointset installed, we attempted to gap the points to the required .010. You can again rachet the crank until the contact heel of the points is on the tip of one of the distributor cam lobes, meaning the contact-breaker points are fully open. Then, the Allen screw can be turned in or out for adjustment. The issue is that the newfangled "set" makes it impossible to get a straight shot with the feeler gauge. We bent ours up and got it as close as we could. We also cleaned up the weights and added a small dab of grease to each one.
Photo 15/25   |   We were going to leave the stock coil alone, but then we decided to remove it at the last minute. First, we removed the wires, then we unbolted the bracket from the manifold.
Photo 16/25   |   The reason was we came across this Pertronix flame throwing coil and decided to add it to the mix. Then we transferred it into the new bracket.
Photo 17/25   |   We compared whatever our old cap and rotor was to the Accel parts. The Accel parts were noticeably thicker and heavier.
Photo 18/25   |   The new rotor was installed onto the distributor shaft next.
Photo 19/25   |   Then, the Accel cap some followed. Ever wonder what that little silver door on the distributor cap is? You're about to find out.
Photo 20/25   |   But first we installed the Pertronix coil back in the stock location and reinstalled the wires.
Photo 21/25   |   Finally, it was time to install the Duralast plug wires. There were five different sizes, so we picked them accordingly. On small block Chevys, the 1-3-5-7 cylinders run from front to rear on the driver's side, with 2-4-6-8 across the way. We started with the standard #1 terminal on the cap, and wired the distributor in the SBC 1-8-4-3-6-5-7-2 configuration.
Photo 22/25   |   Now we could fire the truck back up! We used our handy Harbor Freight timing light to set the ignition to the required eight degrees advanced, or before top dead center (BTDC). Adjustments are made by loosening the distributor hold down tab and moving the distributor ever so slightly clockwise or counter-clockwise. Soon, we were dead on.
Photo 23/25   |   We could see the dwell angle was off by the initial hard starting of the engine. Dwell angle is what you are setting with the point gap, but using a dwell meter is much more precise. The specs for this engine are between 28 and 32 degrees of dwell. With the red on the minus side of the coil and the black grounded, we showed about 34 degrees of dwell; we slowly adjusted the Allen bolt through that little silver door on the distributor cap, and soon were dead on at 32.
Photo 24/25   |   Of course we did a little tidying up, but the real reward was the fact that this engine immediately started better, idled smoother, and we swear it even got a little quieter.
Photo 25/25   |   We made our next cruise, and what a difference our cruise up Pacific Coast Highway was compared to a couple weeks before! Check back to see what else we did to make this old project road-worthy!

Source Box:

Duralast Parts
Duralastparts.com

AutoZone
866.853.6459
AutoZone.com

Pertronix
909.599.5955
pertronixbrands.com

Sources

Auto Zone
Memphis, TN
901-495-6500
http://www.autozone.com
Duralast
Memphis, TN
http://www.duralastparts.com

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