Tom,
The picture Bill posted shows specs.  The Eickman Y Block book also has a chart of cam specs.
My guess, which means I might be totally wrong, about regrinds is that different grinders grind the cam in different ways.  While there may be a precise duration at .020 or .050, there is not a precise spec between those and between .050 and the center line, so the shape of the lobe can be altered while having the same specs on paper.  So while a grinder can duplicate the stated specifications, they probably cannot duplicate the exact profile and that accounts for the difference.



Lawrenceville, GA

I didn't see John's comments on "jerk". But in physics, its distance-velocity-acceleration-jerk-snap. So I assume it's something to do with the change of acceleration of the lift as you move along the ramp of the cam. This would make Charlie's guess correct. With the cam Dr. and a computer program, you'd probably get all this info. My differential calculus is from the days of slide rules, so I don't understand any of this as it applies to camshafts. It's likely more of a concern for long duration high lift racing cams, valve train harmonic, valve float, than it is for street units.

A few months back when I was picking out a cam, either Ted or Greenbird sent me this article. It's one of many out there, and there's a lot of debate even among experts.

http://www.hotrod.com/how-to/engine/0607phr-camshaft-basics/#__federated=1

Sorry to get OT of the OP



miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Properly done regrinds patterened after an original stick specifications will have the same lift and centerline.
Since material is being removed from the camshaft ,the grinding procedure creates a smaller base circle.
The smaller base circle effects the acceleration and closing ramps which in turn effects the jerk rate (and more).
Usually there is a minimum amount of material removed from the stick to get the lift back to where it once was.
Since every stick is worn differently the regrind procedure for each stick requires different amounts of material to be removed to get it back to original specs.

This differing amount of removed material from a worn stick creates a new , different from O.E.M. base circle.
That new reground base circle geometry starting point then leads to the creation of new  acceleration and closing ramps profile different from stock. These new profiles are unique to each regrind.
Again only a small amount of measureable differences but enough so that it should be mentioned.
That would be some of the differences between a regrind and a virgin camshaft.

Oldmics

I had regrinded cam from stock stick. It had quite odd grind, 8mm lift and 290/300+ degree in zero lift but .050 degrees was same what about 285 stick would have.

Couple of noses worned out soon.

I learned that, burnouts are not a proper way to drive a new cam in.


Hyvinkää, FI

Chigger: re your question about other early years cams. Apparently the specs vary a bit, but most are similar to the last replacement cam & are all milder than 1957. As far as is known, all regular car 272,292 & 312 cams in 1957 used the same specs, hence the higher power ratings. It's unfortunate that spec cam isn't readily available off the shelf. 


Paul

I now think it doesn't really matter to me which stock cam I use, it's just me being picky to wish for the very best performing "stock" engine. I have a NOS Ford cam with a B8AZ number, which should have originated in 1958.  I will try to find out what the differences are.

Many thanks 



Tom from the chiggerfarm located in the beautiful Heart of Central Texas

When you cannot dazzle others with your brilliance, baffle them with bullcorn!

Greetings to all: I too have been on a hunt for the EDB cam used only in 1957 part no. B7A-6250-B.  It had a unique grind, with intake lift of .272 and exhaust lift of .285 making it easy to identify with V-blocks and a dial indicator.  It worked extremely well in my 57 312 with it's higher compression ratio, 3.56 gear in the rear and a cruise-o-matic. It also produced the most throaty coolest intake sound only unique to a y-block among many other attributes. That being said, I just finished a lengthy conversation with Ken at Oregon Cams and they indeed have the lobe masters produced from an original Ford cam if anyone is interested.  Ken also confirmed 114* LSA ground 3* advanced. They don't have one on the shelf at the moment but will produce one for me in about 2 weeks very reasonably priced. I'm making a 312 out of my 64 F100's 292 with G heads and 1.54 rockers and this cam.  Hope this helps.....JEFF


64F100 57FAIRLANE500

Greetings to all: Hopefully in about 5 weeks I will be assembling my engine with the "EDB" cam from Oregon Cam.  Will put the degree wheel on with a new timing chain set and see precisely where everything is at. I'll post my findings as soon as I can.


64F100 57FAIRLANE500

Thank you for that information Jeff. That is exactly what I want also. I eagerly await your results. Thanks



Tom from the chiggerfarm located in the beautiful Heart of Central Texas

When you cannot dazzle others with your brilliance, baffle them with bullcorn!

Jeff
As you mention
"It had a unique grind, with intake lift of .272 and exhaust lift of .285"


However according to the information that I have (Eickmans book) the lift on the stock B7A 6250-B stick comes out as
.260 Intake
.272 exhaust
A bit different than the specs you have. I have never seen the LSA specs and advance information published anywhere.

As for the 58 replacement/detuned camshaft the general comparison would be reduced lift .252  along with reduced rocker ratios  (a return of the1.43 ratio) utilized on the 58 and up engines.
That combination would make for a real low performer engine .

It would be interesting to see if the Oregon cam grind is actually the same as the original B7 6250-B.
Ask Ken if he can share measurement information on his camshaft at the points of
.015 on the I.O  and the  I.C. events
and
.013 on the E.O. and also at .016 on the E.C. event

That would tell if the ramps are the same as Fords original cam or if its something different.

.
Oldmics