WerbyFord":2kdtwqxv said:
Ive yet to figure out why Ford retarded those cams so much. After about 1972 it was done for emissions reasons and makes engines a real dog. Common v8 trick on any post-1972 Ford (most anyway) is to advance the cam 4 to 8 degrees, really wakes em up.
Yet, as I look up the stock 200-250 cams, they are indeed retarded. Ive never measured one but cant figure why.
Were the early cams retarded too? Why?
Regarding mileage and matching the original, x2 on measuring what you have before you take it apart.
And, the "256" factory duration may not match up with aftermarket stuff as they are measured differently.
The factory cam was about 185-185 duration at .050" lobe lift, that is the common measuring point.
So you'd want a cam in that range.
I built our 289 v8 with a 194-204-110 cam instead of the stock 184-189 duration. It really woke things up but did not cost more than about 1mpg highway, from 21mpg to 20mpg. I would not however exceed that 194-204 duration. Crane lists a 194-204-110 cam for the Falcon 6, I'd be tempted to get that one if you want to keep the MPG up. Probably a Pinto carb would be the best bet on top, they are very good on gas and just about the right size for that cam.
So I would still appreciate any insight on why FOrd retarded those cams from the factory, looks like they did it even before the Smog era!
THINKING ABOUT IT to answer my own question:
Why might Ford have retarded their cams?
They almost never run better or even as good retarded, unless youre at Talladega or Bonneville with really big heads.
Of course from about 1972 up it was often done for emissions reasons.
But Ford ran retarded cam specs way early too - on the 215-223 Mainline Six, on some of the 170-200 Falcon Six, and even on some of the 289 vanilla cars. However, Ford did NOT retard cams on the very smallest engines eg the 144 Six, the 221 v8, the Pintos, nor on the bigger v8's. Where is the logic?
I dont know if this was Ford's logic, but here is a possible logic, comments or insight welcome!
* Retarding the cam:
* Gives better or at least the same top end in general
* Hurts full throttle midrange and low end torq in general
* Gives better emissions (but nobody cared in the 50s-60s)
* Can give better MPG at part throttle (you let the power stroke do more work, and it still has plenty of time to get out since youre only at part throttle)
Could the last point by why Ford did this? To get the maybe 1mpg better on those "small engine" cars (six and base v8 small cars)? Thats all I can think of. Other than that reason, I've never seen any dyno data to support running retarded like that.
My theory is, the little 144 Falcon, 221 Fairlane and the Pintos etc were SO underpowered, they wouldnt handle a retard so these engines did not get hit with a retard. And the bigger engines were set up to RUN, so the trick wasnt used on them either, nor on the truck sixes, since they were meant to pull hard, not to be easy on gas.
So thats my theory, any comments welcome.
since you are doing a minor upgrade in the cam, and want to maintain the low end torque, you want the 112 lobe separation angle, unless you are bumping the static compression ratio above 10:1. remember this is about cylinder pressure at lower rpms, the higher, within reason, the better. but like anything you can go too high, and then you run into detonation at low speeds under load.
really the only reason IMHO
