Ford's new thing is the OHC(Overhead cam) motor. Hot Rod TV, devoted a whole episode soley to the 4.6L Mustang motor, and how OHC was alot more powerful/effient than the "ancient" OHV style. OHC motors I agree do create more low-end torque (seems more like a truck design than a muscle car design), than the pushrod motors(what Chevy uses). If OHC is so much better than OHV, why does Ford go right to the supercharger to create more power?? the Lightning is rated at 380HP-380lb-ft. Really good #'s and makes for a fast truck. the SS Silverado is 345HP, not exactly sure on the torque #'s. Lets say we take that superhcarger off the 5.4, that would drop the HP down to around 300, along with the torque. One good thing about the Lightning is RWD, I wish Chevy would take that god-awful AWD off the SS.

 

If the 4.6 Mastang is so much better, why is it a known fact that an "ancient" 1995 model with the OHV 5.0 will stomp in into the ground? In fact, when the 4.6 came out in the Mustang, it was SO weak that Ford finally had to virtually redesign the engine for the '99 model year because of all the complaints.

If you ask me, OHV is the way to go. It's a proven design, makes more power sooner, and is cheaper. Maybe that's why GM has stuck with it. GM always has known how to build a REAL engine.

 

i just saw picture of a indy car motor and it was dohc design. also some(most) of the exotics use dohc motors. i always thought they were more of a high reving motor. i always wondered how ford claims more low rpm torque.

 

Ford uses a supercharger for the same exact reason Pontiac does on their GTP. If you were to take a 5.4L to 380HP without one it would idle very rought and would not be very streetable. Ford wanted you to be able to hop right in your truck or cobra and cruise anywhere you want to go without even a worry about hard starting, overheating at lights etc.....

WXBoy: The 99 models got much higher flowing heads. The placement of the cam had nothing to do with the lack of power. There was no 5.0L making as much power as the new 4.6L.

 

How does OHV make more power sooner when the two could be set up with the same specs.? Both could have same lift ,duration, approach angle, I guess I'm confused.

 

You're not confused Dude. The OHC engine would be using lighter valve springs also.

 

It COULD be, but they aren't. The Ranger is a perfect example. The new SOHC version of the 4.0 makes 45 more horsepower. But, it doesn't make it until 5,200 RPM. Who drives around at over 5,000 RPM?? If you compare OHV engines of the past to the "new" OHC counterparts, the "old" engines made power sooner, and therefore they almost all feel stronger because their peak power is in a more "useable" RPM range.

And no, the 5.0 never made the kind of power that the 4.6L does NOW. But it's only been that way since 1999. The heads were changed, and so were other internal engine components. A 5.0 car will destroy a 4.6 car made before they finally went back to the drawing board in 1999. We've had both...and we agree the "ancient" 5.0 is a lot more motor for the money.

 

I never just look at peak. The whole power band has to be considered. My 1992 crown vic with the 190HP 4.6L and 3.08 gears will burn the rear tires pretty easy. It stalls pretty low too. I think it has plenty of low end torque. The 302 was never a low end torque monster and in my opinion should have stayed out of trucks and in mustangs where it did very well.

 

but the RPM power curve is not based on wether the cam is above or below the heads. It's the way the new engine and cam itself is set-up. I still don't see how having OHC takes longer for the power to come on. Just change cam specs. I'm not trying to be annoying, but I was looking for technical info. to back up the statement. Not just the fact that the newer engines have a taller power curve.

 

I agree with duderoy. Ford could design an OHC engine to be a torque monster or a super high rpm rever. They can do the same bore, stroke, cam, internals, basic head design, and ports to a pushrod OHV engine and be close. I believe that if they made an OHC and OHV engine to be as close to even as possible, they would be very close power band wise, with the edge to the OHC because they are more efficient. They just design engines different with newer technology. Just my $.02

 

I agree with Ratsmoker...the 302 should have stayed out of the trucks and in the Stang. I also had a F-150 with the 302 and it was the worst truck engine I've ever owned.

You guys are right, they could setup the OHC motors to bring the power on quick like the OHV engines do. But for some reason they haven't. You have to hit 3,000 in most OHC vehicles before you even start to get any kind of power. And that to me just doesn't seem like the most efficient design possible.

 

They're designing them that way for numbers. its easier to look cool with the fat horsepower numbers if you go higher in the rpms. Also - when you romp the gas pedal you're going to kick the vehicle into that 3000+ rpm zone the whole time anyways.

 

Well heres my outlook on the new OHC vs. the old. The 302 never made the low end torque that the smaller 4.6L does. The 351W never made the low end torque that the 5.4L does. Also they are making bigger horsepower numbers with the most recent designs. This is talking truck engines only of course. I won't get into the V10/460 deal because I can't honestly say the V10 makes more low end but we are talking a bunch or displacement difference. I don't think ford really ever got into the horsepower race with its work trucks.

 

Placement of the cam has nothing to do with the effective RPM range of an engine. Look at the '96-99 Cobra engine. It was definitely a high winder. It would scream to 7000 RPM's. Chevy makes a good small block. The LS1 is one of my favorite engines. It is a OHV engine and it likes the RPM's.

Wxboy,
You can't have it both ways. You say the OHV design makes power sooner and it is a proven engine, yet you like GM motors. Take a look at their 5.3 torque curve vs the 5.4 and tell me who makes power sooner. The new 3V 5.4 makes more torque from idle to redline than the 5.3.

 

In theory I really don't agree with this and here is why. With an OHC engine you can increase the cam lobes aggressiveness without changing the gross duration. This is due to the much lighter valvetrain mass. This will yeild greater power across the board.