which is better? DOHC or PUSHROD V8?

 

Neither is just outright "better." Both have their strong points.

For bolt-ons, H/C, N2O (basically N/A or on the bottle)...LS1.

Want boost...the DOHC 4.6 is hard to beat. They respond very well to boost and can easily handle quite a bit of it. Even before the iron block and forged internals (in the '03 and '04 Cobras), a stock DOHC 4.6 could (in most cases) take 12+psi without a problem.

 

Pushrod engines always make better
power down low. Ford DOHC need to rev
and have little TQ feel especially the older ones.
If you like your LS1 you probably wouldn't like
the other.
Speaking N/A

 

That makes no sense whatsoever...

How do pushrods make more power down low? you're comparing different engines.. one a GM, one a ford... I mean, come on...
I seriously don't see how pushrod engines can make more "Torque" or whatever than OHC engines.. considering OHC would have no real lag when opening and closing valves.. the cam is RIGHT THERE to open it.. where as pushrods rely on the movement of the rods and the rockerarms...

 

Whether some want to believe it or not, Ford's 32V 4.6L is almost as good as the LS1 in terms of naturally aspirated power.

The '01 Cobra and the new Machs are in LS1 territory when it comes to 1/4-mile times, even if the Fords put down less power.

The only downside to the motor is that it's heavy, but the motor is also hand-built. How can you beat that?

 

I think he was referring to the fact that the 5.7L makes more torque down low than a 4.6L engine. This makes perfect sense considering the displacement advantage the GM engine has over the Ford engine. I have owned 3 different F-bodies and driven a blown '96 Cobra. For the money put into it you still needed a good amount of RPM's to really feel some thrust.

 

apparently GM stayed with PRs due to that fact that it makes better power down low without having to rev it high.other reasons were cost and they take up less space.


another thing about ls1s is that despite what some people want to believe is that they make excellent power under boost and hold up well if theyre tuned correctly.

 

What's this crap about pushrods making more Torque?

All that crap depends on intake design, displacement, the ability of the engine to breathe, tuning, and all that crap...

Which I'm sure GM and Ford both have different designs... I don't see how pushrods would have anything to do with making more torque down low...

 

I didn't say the pushrod design is the reason it's making the torque down low...I said it's b/c of the displacement advantage.

 

Yeah, I know. And that is correct....

I was referring to the other people's statements.

 

I lean towards pushrods...

The 4.6L DOHC engine is huge.. Its bigger than your olds school big block. and its very heavy.

the new LS2 now brings 400 hp to the table.. without gaining any exterior size, and even losing about 15 lbs of weight.

So lets see. the LS family is smaller, lighter, cheaper, and produces more HP, at least in NA form. That pretty much settles it.

The blown 4.6L and 5.4 are pretty sick though.. and they better be considering the huge size and weight of the blocks, heads, supercharger, intercooler, and assorted piping.

But, I rather have a 427 LSx or C5R.

whatever dohc gains in flow and potential revs, the pushrods make up in being able to pack more cubes in a given space.

 

Can't understand how an engines internal
design could effect its powerband/output?
Then I guess each individual compenant has
to variable either-rocker arms, cam, etc...
Lets take 2 similar outputted Ford engines.
The 5.0(pushrod) and 4.6(OHC) both rated
in the 225HP neighborhood. Guess which
one runs on the high end, guess which
one has more get up and go from a stop.
Think they perform identically?
Ever look at a truck engine's output
and design-You aren't seeing many OHCs

As far as LS1 vs Ford, they may or may not
have similar 1/4's (depending on year) but
drive an LS1 on the street in normal use.
You'll see a lot more power without pushing the
hell out of it (say under 3K RPM). Yes displacement
is a factor.

Its really no secret that pushrod motors pull stronger.
You have to really rev up OHC to get the power up of
them(not saying we make peak low either).
Its hard to take displacement out of it but since
Gen III V8's all the smallest pushrod and Ford 4.6
in the largest OHC(that I can recall)
its the closest comparison

 

I'm going to try to stay out of this little OHV vs. SOHC/DOHC argument but I'm just going to throw some facts out here:

The largest OHC motor Ford has built would be the 5.4. Your run-of-the-mill DOHC 5.4 (like in the Navigator) is rated at 355 ft/lbs (at 2750 rpms). There is also a SOHC 5.4 in the Ford trucks and SUVs. The two valve is rated at 350 ft/lbs (at 2500 rpms) and the new three valve is rated at 365 ft/lbs (at 3750 rpms).

Then there was the DOHC 5.4 that was in the '00 Cobra R. That 5.4 was making 385 ft/lbs (at 4250 rpms).

And don't forget the LT5. The '93-'95 ZR-1s were also rated at 385 ft/lbs (at 4800 rpms).

None of these motors are really pushing the limits (IMO) so the above isn't even valid if you want to talk about which one wins when you can throw tons of R&D and money into them. Although, I'm sure the LT5 and the '00 R's 5.4 did have plenty of R&D put into them already.