7/18/2023 0 Comments Sbc timing cover differences![]() ![]() You'll find that aftermarket dampers are the 10º type, as are the bolt-on tabs sold by the aftermarket, unless they're adjustable. The damper used from 1969 to about 1984 has the TDC line at the 2 o’clock position- or 10º before the keyway. The keyway is seen in the ID of the damper nose. the line is to the LEFT of the keyway, looking at the front of the damper or engine. The pre-1969 damper has the TDC line on the outer ring at the 2:30 o’clock position- or 2º before the keyway centerline- i.e. The exact years of the type of damper timing marks overlap one another, depending on the exact application. The three most common locations for the timing mark on the damper The balancer was also very light for an 8" balancer." The tab was welded to the timing cover instead of the usual bolt on tab in those years. I had a 76 350 truck core that had this balancer and timing mark on it. I don't know if any 400 engines were built this way, I really doubt it. You have to point the timing light through the gap between the water pump and timing cover. Only a few 69-up engines were made this way. #3 is the balancer TDC mark is 30 degrees CCW from the keyway, again looking at it from the front. There is a bolt on timing tab that works with this setup. ![]() This is the most common location for 69-up engines, and that includes 400s. #2 is the balancer TDC mark is 10 degrees CCW from the keyway, looking at it from the front. This would not include 400 engines since they were all made after 1968. There are two timing tabs for this, one for 6"+ balancers, and one for 8" balancers. This is the configuration for 1968 and older balancers. " #1 is the balancer TDC mark lines up with the keyway. Plus the tab location varies with small and large balancers as far as the distance from the crankshaft. There are 3 timing mark locations on the balancers on SBC engines that I know of, therefore there are 3 timing tab locations also. ![]() Stock timing marks are very limited in the extent of timing changes that can be indicated These things are a deceptively simply but necessary component on your engine, they range from the cheap stamped steel, and non adjustable versions to the much nicer adjustable versions, ONE basic thing youll need to know is where TDC, 90,180,270 degrees are located if and when you get involved with tuning your engine ignition timing advance curve or adjusting valves if you do in with the engine not running, ignition spark should be bright blue and impressive, if its, weak,narrow, yellow or red theres a problem so research the cause, verify the coil and voltage ![]()
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