Hi All, I noticed that the rated horsepower on the 1972 250 is quite a bit less than the earlier motors. I know that the rating method changed that year, but what else is different? I would like to make the six as powerful and efficient as possible, without radical changes like the 2 barrel carb, which is apparently not cost effective. Already did the Duraspark II mod. Don't want to go to headers, radical cams, etc. This is a around town everyday driver, not a race car. Looking at the various parts sites it seems the part numbers for the heads and cams are the same. Only difference is the valve advance timing. If you go to the Cloyes website and check out the "Parts Detail" pictures for the cam sprockets it is very apparent that the timing is retarded on the later cars. Other than this I see no other changes. Any help would be appreciated. What about EGR valve, other stuff that may effect power/efficiency? This is a Kalifornia car. Thanks, Karguyz in Taxifornia
Has to do with the way they rated the horsepower on the engine. 72 and earlier they took the brake horsepower, or hp at the flywheel. In the later cars, they took the readings at the rear wheels, with all accessories on and running. Made a big difference, but the engine was the same. Make sense??????????
Ford retarded the 250 timing in '72 twice for better emissions numbers and this caused less power. This was done with more advance on the timing gear's keyway. The '69-'71 chain/gear set is more aggressive. I'm sure your EGR tube is clogged solid by now if still original so removing the EGR will not see any improvements in performance. Although some cams will have the same lift/duration the lobe center will vary.
Lower compression; leaner mixture (EGR); retarded timing; different cam and cam timing. If you want to regain the lost power from 1969 you have to get flat top pistons, the older distributor (or advance mechanisms), carb, cam and lifters, and timing chain and sprockets from the earlier model.
