Mike the Radiator Man's
Tech Tip #2 , Retarded Cam Timing
If you have installed a later model engine (early 70's to early 80's) in your Fairlane you might be in store for some free horsepower for that engine. How would 5 to 10 low end torque type horses grab you?
In 1972 Ford began producing low lead compatible engines and cutting back on true horsepower output. Many required design changes were to meet Federally mandated tailpipe emission regulations. Some of these changes involved lowering compression ratios, leaning carburetor mixtures, adding air injection to exhaust gases, and retarding cam timing events.
Ford accomplished the retarded cam timing by off setting the timing gear key slot by as much as 6*. When you are rebuilding your engine or by refreshing the timing set, it is easy to restore this straight up timing by replacing your original timing set for a pre 1972 set. This applies to 302,351,390,429, and 460 engines. You will note the 428 is not listed, because the 428's were not produced after 1971; therefore, there will not knowingly be any retarded 428's.
There are 3 ways to correct retarded timing:
#1 Use an after market off set key.
#2 Use a pre 1972 timing set.
#3 Install an after market multi slot timing gear.
This modification is great for street type engines because it produces all it's gains in the low end torque and responsiveness. That is just where we need it most in drivability.
If you think about this retarded timing and how it robs your engine, you can visualize how a worn engine can retard it's self with high mileage. The worn cam lobes, cupped lifters, and stretched timing chain all allow the timing to occur later and later, while the engine becomes lazier and lazier.