great thread with some excellent info. id just like to point out on the cobra r, that while it was making 385 or more n/a hp it also had headers and bassani mufflers and sidepipes from the factory, thats an easy 20hp not to mention the gigantic intake manifold that needed that hood to cover it up and the lack of a/c to spin too. just my minor contribution to this thread. also the 5.4 never went into the mustang because it was too big and the shock towers had to be moved to make it fit, thats why they only made 300 r's.

 

Don't have to move the shock towers - it fits in there, barely. Also, the R's engine ran a 9.6:1 CR (pretty lazy CR for a "race" car if you ask me, but just my opinion) versus an LS1 at ~10:1 or 10.5:1 for an LS6. The exhaust system has been replaced on some cars with a different Bassani X-pipe and matching catback - combined with a good tune netted one guy I can think of off hand ~395 at the wheels. So, while it has aftermarket exhaust parts from the factory, there's still plenty of power in the exhaust.

 

sounds kind of like the LS7 design, it would be sweet if someone made those for LS blocks

 

ooh, just saw they make em for SBC's too. what is different about SBC heads that(i assume) they wont fit on LS's?

 

sorry for the triple post but im posting as i read.
they also make them up to 4.060(6.0 LS1 size)bore
cost a pretty penny though

 

give it time and you'll hear something. my dad and i have been working with russ to get this project rolling. the biggest thing would be intrest. theres alot of haters out there that dont like this design. it's gonna be interesting on power numbers. hopefully i can get a beta set and report on figures. but thats gonna be a while from now

 

I remember hearing or reading that two larger valves out flow four smaller valves that are in the same head. Anyone else heard this before? However, huge valves and huge runners, equals loss in velocity, doesn't always equal more power.
But with the cam over the valve you have no need to change the direction of movement with the use of rocker arms. Any change in movement results in power loss.
I are not no college graduate but, I thought I would voice my opinion. I like the Gen III small block more than any SOHC or DOHC.

 

i've never heard that two smaller valves will out flow four smaller ones. the smaller valves should cover more surface area which in turn let more air in or out.

 

I am going to add to this thread probably because of being in a position to give a relatively unbiased opinion. This is due to having both types of engines and have driven both for quite some time. I have a 2001 Z28 SS, a 2003 Mach1 and a 2005 CTSV. I purchased the Z28 and the Mach1 both used with less than 10,000 miles on each. Both cars are manuals. Both cars were purchased with the intent of keeping them the rest of my life if I could afford to do so. I felt at the time that both were low enough in production numbers that one day down the road would be classics in their on right. Both are great cars in there on right. It did work out to be able to keep and park both fortunately, so I recently purchased a 2005 CTSV with 19,000 miles on it to drive on a regular basis. The Mach1 and Z28 are both currently covered and stored in a garage. Now for the power part. I will leave the ET part out because neither car was ever ran with sticky enough tires on the rear to get that absolutly best ET to be fair about it. But I think you will agree that the trapspeeds would be the fairest way the judge the actual engine. The Z28 would consistently run in the 107 to 108.5 range. The Mach1 would run anywhere from 105 to 108.3. These numbers would be in comparable weather conditions. The difference in trap is due to the inherent difference in the engines that you have discussed. The Mach1 will run right with the Z28 but is very dependent on the driver as seen in the traps. It simply has less room for driver error due to the higher, shorter powerband. The reason for the range in trap speeds for the Mach1 is the smaller engine must hit it's shift marks to keep it in it's higher and shorter powerband. I have out ran LS1's with the Mach1 and out ran other Mach1's with the Z28. Just because this is a LSX based web sight, don't fool yourself, with apples to apples mods the smaller 4 valve motor will run right with it, but it has less room for driving error. I really think that the added torque of the Mach engine versus it predecessors really closed the gap. When the cars were both retired, with longtubes, full exhaust, cold air/lid and tunes the Z28 made 338/335 and the Mach1 made 327/339 on the same dyno and were still within 1 MPH trap sped in the 113/114 range. The smaller cubed 4V needs gears and a driver that can technicaly hit his shifts. Surely if you throw a bunch of money at both the cubic inches will win. It is alot cheaper to internally mod the pushrod motor especially if you throw in a cam or in the 4V 4 cams. But both engines are really strong. After buying parts both both the LS1 is a cheaper route no doubt. In this case it would have been a drivers race. The smaller 4v motor will run, however it is more difficult to make it run. The larger cube Ls1 was more consistent due to the power under the curve. That's my inbiased 2 cents worth. I live both my cars. I love my CTSV. I think stock for stock, it is capable of out traping both the the Z28 and the Mach1, but I think the Z28 and the Mach would get there first in the 1/4 mile because of the lighter weight of the 2 doors.

 

Dont know if it was said yet but I'll start yes the DOHC design can be superior but the thread jumped off base when ford vs gm was started. Its not that the DOHC design sucks its ford DOHC design sucks take example the Ferrari 4.2 dohc makes 490 hp at 8500 rpm but that is a product of better engineering so taking it down a level look at the 95 LT5 motor DOHC and 405hp@5800 rpm last year for the LT5 and ford hasn't even put there DOHC motor out yet. so even before it was made it was already outdone.

 

Anyone take the time to notice this thread was from 2004?

 

But then again Id rather have 580whp @ 5800rpms, than 600rwhp @ 7500rpms...

 

this thread is from 04...

 

yay for resurrected threads

I think peed is essentially correct, however I would say only up to a certain power level. Once you start going above 500-550rwhp it seems to me from when I had my Mustang theres almost nothing you can do with the 4.6 to make more power until you get into race gas, stupid compression, etc (that number is bored and stroked already) we have 427+ci LSx motors pushing 650+ N/A at the wheels with way more left. in the end I think the DOHC technology in the 4.6 is somewhat limiting for high end power

 

Lol with the help of the LS1tech flux capacitor we can travel back to old threads with just a click of the mouse

 

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who cares how old it is, its still relevant isnt it?

atleast the search ****'s will be happy someone used the search. god forbid someone posted this topic without searching it first. Some smart *** would have posted a link to this thread and would have said use the search!!!

 

I think the answer to this argument is simple 2V can not beat 4v on a similar sized bore. Now either can be made to make power, to say pushrod is old dead technology is just plain stupid last time I looked GM’s LS7 has a cam in the block but out powers Ferrari and Lambo while putting out more lowend and getting better fuel economy.

Now to ford modulars ha you knew I had to say something. Stock I see one thing that ford should have done that would put the 4.6's power levels at that of the LS1. That is to use a variable intake (one that switches from long and short runners) like the FR500. The FR500 itself was a good product but not designed for mass production being made of magnesium and all but a similar intake was put in Lincoln Aviators and was much cheaper proving that it could be added to engines a minimal cost. I've seen 4.6's (stock cubed) with fr500 cams (which like said way back in 04 in this thread have similar duration to cams equipped stock in LS motors) and intake that put out 300rwtq at 3,000rpms and well over 350rwhp. Yes this was with a full exhaust but that would not help the torque #’s at 3k and even with a stock system I’d bet it would still be able to make 320rwhp.

 

There wasn't a new question that resurrected this thread, it was a response to something someone had posted circa 4 years ago.

Damn take some Midol. No I don't think it is really relevant either, since if you had actually read the thread both sides had placed up good debate topics, that degraded into a GM vs Ford argument.

 

It’s been 15 years. How well has that worked out for GM and the LS platform?
Quickest Ford modular powered Vehicle in the ¼ mile 6.083 @ 236
Quickest GM LS powered vehicle in the ¼ mile 6.73 @ 206
There are 5 Modular powered vehicles quicker the that and the gap is getting wider!