460 .40 over

[lon]

I have gotten about six different answers for how many cubic inches a 460 bored .40 over would be and with stock cam, Carter 625 AFB carb and stock heads how much horsepower and torque approx. would it produce.

[cycleguy55]

Bore: 4.360
Bore +0.040: 4.400
Stroke: 3.850
Displacement:
Formula: (Bore/2)^2*Pi*Stroke*# of cylinders
Calculation: (4.400/2)^2*3.1415929*3.85*8=468.3 CI

Others will have to weigh in on HP and torque, but my view is 625 CFM is not enough carb - though it could be with stock heads and cam. You might want to check with the folks at http://www.460ford.com/forum/

The heads have been opened up a bit on my 460 and it's running an aftermarket cam - and I'm not convinced the 770 CFM carb is big enough. Having said that, it does start and drive well on the street, and that's pretty much all I intend on using it for.

[Tom Wells]

lon,

Well, there's only one answer to the displacement question: 468 cubic inches. The stock bore is 4.360 so 0.040 overbore gives 4.400; the stock stroke is 3.850 so you can easily verify my arithmetic.

The other half of your question has no precise answer because there are too many variables such as what original engine you began with, compression ratio and any other non-stock mods you may incorporate in the process of putting the engine back together.

Stock 460s came in a variety of horsepower ratings. Here's a sample of what I mean quoting from a web site at Engine Specs, Engine Information, Firing Order, Horsepower Specs : Engine Facts.com

1968-1972 Ford 460 with 4 Barrel Carb
Max Brake Horsepower - 365 @ 4400 rpm
Max Torque – 388 @ 2800 rpm
Stroke - 3.85
Bore – 4.36

1973-1996 Ford 460 with 4 Barrel Carb
Both horsepower and torque for the 460 from 1973 until 1996 changed many times depending on emission controls, various fuel injection and carburetor setups as well as what the engine was used in. For the most part, the max horsepower stayed between 205 and 275 hp for any factory built motor with max torque ratings between usually being between 345 and 375 lbs.

You see what I mean: max hp varied from 205 to 365 depending on the year and what vehicle it was installed in. There are differences in head configuration, whether it is/was a smog motor etc etc.

Suffice it to say that with a mild hydraulic cam and very little other mods it could easily prove adequate to propel a kit Cobra for quite a few thousand trouble-free and smile-filled miles

Tom

[lon]

Edelbrock uses this formula to size a carb on their web site.

street: displacement x max. rpm x .85 divided by 3456 = carb size for street apps
race: displacement x max rpm x 1.15 divided by 3456 = carb for race apps

on my car: 468ci x 5500rpm x .85 divided by 3456 = 633 cfm

[cycleguy55]

For my 460 @ 6,000 RPM, 0.85 gives me 679 CFM, while 1.15 gives me 918 CFM. I'll leave the Holley 770 Street Avenger on it, but I do have an 850 Double Pumper in a box should I ever decide to take it to the track.

[Tim Brewer]

A lot of guys think you gain noticeable cubic inches from over bores, but in reality you don't.

[mdross1]

As you have read without knowing a lot more about your 460 it is next to impossible to give numbers on hp and tq. If all you are doing is freshening up your 460 the overbore will add very little other than bringing the engine back to what it once might have been.
The 625 will work fine with stock internals,our 460 for example has a custom built 1000cfm dbl pmp Holley it works as good as we hoped but the engine is built for it.

460 Ford Forum will be a good place to visit as well

[Large Arbor]

My vehicle came with dual 600 Holleys on my 468 FE and it seems to be just right for the street....Although with it being 12 degree this morning with salty roads, I could not bring myself to take it out today. (: