To some, the intricacies of setting the ignition timing on an engine or changing a distributor may as well be black magic, while to others it's a procedure they know by heart, and as we took the opportunity to replace the cheapo distributor and coil in my '46 roadster pickup with Pertronix Flamethrower versions before I drove it to Bonneville, it offered the chance to delve into a subject that might be of interest, if the number of times I've seen people confused by timing markers and the subsequent inability to set their timing is anything to go by.
The following is specific to the small-block Chevy but is more common than you'd think, given the number of late engines stuffed into small engine compartments on the average hot rod. See, oftentimes to gain those precious few extra inches of room, the long water pump on 1969 and newer small-blocks is swapped for the earlier, shorter version. Not a problem you may think, but this means the new pump is now hard up against the timing cover, and the timing tab is now impossible to see, or may even have to be removed for clearance. Also, if an aftermarket cover is used it'll more often than not have no marker on it.
The answer is generally purchasing a bolt-on timing tab from a supplier such as GM, Mr. Gasket, Speedway Motors, or Summit Racing. Sounds simple huh? Well, yes, two bolts and it's attached to the timing cover, but it's not in the right place to correspond with the timing mark on the harmonic balancer, and you'll never set the timing correctly unless the mark is moved to correspond with the new tab. Forgive me if this isn't news to you, but it happens time and time again and must be the number one problem when trying to set the timing on a new engine.
With that tip out of the way, we'll move on to installing the new distributor, now that piston number one is guaranteed to be at TDC. Again, it's probably not rocket science to most, but worth repeating. The Pertronix Plug 'n' Play billet distributor has a factory set performance curve but is supplied with additional springs to customize the advance curve for specific engine requirements. We used it as it came out the box. It can be used with a multi-spark CD ignition box, the electronics acting as a trigger, but as my truck is hardly a performance vehicle, we opted to combine the Flamethrower distributor with one of Pertronix's 0.6-ohm 45,000-volt Flamethrower II low resistance coils, which doesn't require a ballast resistor.
The Ignitor II module in the distributor is similar to the Ignitor that has been available for around 30 years as a replacement for points in regular distributors, and senses the current levels in the coil, adjusting the dwell period for the best possible spark over the RPM range. I can report the engine ran much more smoothly with the Pertronix distributor compared to my old stock distributor and performed faultlessly for the 2,200+ mile trip to Utah and back without missing a beat, unlike some of the other components on the truck, but that's another story!
