7.3 Gas Swap...Oh Yes.

[Nothing Special]

I think its more based on operating RPM. With 6 gears at 55mph your basically idling.

I think it's a lot more than that. There's no way a 460 is going to return 18 mpg highway with a gearing change. Like Gary says and more, heads, cam, valves, intake, exhaust.... Much of what you can do aftermarket to improve power output actually improves engine efficiency. A more efficient engine makes more power out of the amount of air and fuel it can pull through. If you don't use that extra power the vehicle can use less fuel to do what it used to do with more. Some engines have more room for improvement than others!

So could a 460 be built to give similar power and efficiency to a Godzilla? I'm sure it could be better than stock, but it wouldn't be cheap or easy, and maybe not possible to get the whole way.

But most newer engines are inherently more efficient than those of a few decades ago. The car companies have invested a lot of R&D to make that possible.

[grumpin]

I think it's a lot more than that. There's no way a 460 is going to return 18 mpg highway with a gearing change. Like Gary says and more, heads, cam, valves, intake, exhaust.... Much of what you can do aftermarket to improve power output actually improves engine efficiency. A more efficient engine makes more power out of the amount of air and fuel it can pull through. If you don't use that extra power the vehicle can use less fuel to do what it used to do with more. Some engines have more room for improvement than others!

So could a 460 be built to give similar power and efficiency to a Godzilla? I'm sure it could be better than stock, but it wouldn't be cheap or easy, and maybe not possible to get the whole way.

But most newer engines are inherently more efficient than those of a few decades ago. The car companies have invested a lot of R&D to make that possible.

That is MPG I would love to have with that kind of HP and torque!

I assume a lot of it comes from computers used in design and testing.

[Gary Lewis]

I think it's a lot more than that. There's no way a 460 is going to return 18 mpg highway with a gearing change. Like Gary says and more, heads, cam, valves, intake, exhaust.... Much of what you can do aftermarket to improve power output actually improves engine efficiency. A more efficient engine makes more power out of the amount of air and fuel it can pull through. If you don't use that extra power the vehicle can use less fuel to do what it used to do with more. Some engines have more room for improvement than others!

So could a 460 be built to give similar power and efficiency to a Godzilla? I'm sure it could be better than stock, but it wouldn't be cheap or easy, and maybe not possible to get the whole way.

But most newer engines are inherently more efficient than those of a few decades ago. The car companies have invested a lot of R&D to make that possible.

Right, Cory. With the ZF5 behind the engine that's now in Cal's Rusty, Dad's truck got ~14 MPG running 65 MPH. Our calculator says that with the 30" tires and 3.50 gears it was turning 1936 RPM.

But Big Blue's 460 is supposed to be turning 1795 at the same speed. So if it was engine speed BB should get better than 15 MPG. And we all know that's not going to happen.

When I get the EFI on Big Blue I'm going to be able to say "You can't get better MPG than this with a 460" since I'll have a fresh Scotty-built engine, EFI, ZF5, headers, etc. And if I get 14 MPG I'm gonna be thrilled - and incredulous.

There's just something about the design of the 460 that makes it thirsty. I don't know what it is, but it doesn't endear me to that engine. Maybe the Scotty-built engine will at least put a smile on my face - as I fill up with gas frequently?

[grumpin]

Right, Cory. With the ZF5 behind the engine that's now in Cal's Rusty, Dad's truck got ~14 MPG running 65 MPH. Our calculator says that with the 30" tires and 3.50 gears it was turning 1936 RPM.

But Big Blue's 460 is supposed to be turning 1795 at the same speed. So if it was engine speed BB should get better than 15 MPG. And we all know that's not going to happen.

When I get the EFI on Big Blue I'm going to be able to say "You can't get better MPG than this with a 460" since I'll have a fresh Scotty-built engine, EFI, ZF5, headers, etc. And if I get 14 MPG I'm gonna be thrilled - and incredulous.

There's just something about the design of the 460 that makes it thirsty. I don't know what it is, but it doesn't endear me to that engine. Maybe the Scotty-built engine will at least put a smile on my face - as I fill up with gas frequently?

In my 1994 F250 I used to have with the EFI 460, the best I ever saw was right at 13 MPG.

It did have 4.10 gearing though.

Better than my 1986, but the 86 fun factor is higher.

If we had a bad winter, i.e. driving around town slow and in 4WD, I would get about 6 MPG. I haven't checked the 86 in that type of driving, didn’t want to know. My estimate is between absolutely horrible and terrible!