4.0 liters = just under 250 ci. Rather than a long stroke 250, the killer engine could be a 240. It's a bigger package, but with a 4" bore, long rods, short stoke, it could be a high winding performance engine.
Destroked 4.2L? Or stroked 2.8L turbo?
- Thread starter Anlushac11
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MustangSix":28709wss said:
I do agree but unfortunately the classes I was looking at running in say the engine had to be offered as original factory manufactured equipment for that model.
That means if I want to run a I6 I am limited to a 170, 200, or 250.
250's were never offered in that vintage Mustang either.
MustangSix":nttibev3 said:
Unless I misunderstood I can run any engine from another year Mustang as long as that engine was offered as original equipment.
I do not recall the 240-300 engine family ever being offered in a Mustang.
Worst case scenario I will have to stay with the 3.3L motor. I am looking at running Solo in Street Modified.
A
Anonymous
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three Holley 4412 carbs using a welded adaptor like the Falcon Six Handbook suggests, duplicated three times
What's wrong with this picture:
The triple Holleys are on a plenum (common) manifold, and need fairly rich jetting since the vacuum signal will be weak. Each venturi is connected to the entire manifold volume.
The Weber diagram shown is an IR (completely separated) manifold, with each barrel only receiving signal from one cylinder; jetting must be leaner.
Calibrate it like three DCOE 42 Webers
Practically impossible - the Weber has many more circuits, more size choices, and an emulsion tube with staged bleed holes. No analogous part exists for the Holley. Even the Webers would not run "Calibrate it like three DCOE 42 Webers" on a plenum manifold.
You have to decide whether you want an IR (totally separate) manifold, plenum (totalled connected) manifold, or one of the most common, popular and successful designs: each pair of cylinders has its own separate carburetor.
Like Jaguar, Healey, etc. Ever seen one?
What's wrong with this picture:
The triple Holleys are on a plenum (common) manifold, and need fairly rich jetting since the vacuum signal will be weak. Each venturi is connected to the entire manifold volume.
The Weber diagram shown is an IR (completely separated) manifold, with each barrel only receiving signal from one cylinder; jetting must be leaner.
Calibrate it like three DCOE 42 Webers
Practically impossible - the Weber has many more circuits, more size choices, and an emulsion tube with staged bleed holes. No analogous part exists for the Holley. Even the Webers would not run "Calibrate it like three DCOE 42 Webers" on a plenum manifold.
You have to decide whether you want an IR (totally separate) manifold, plenum (totalled connected) manifold, or one of the most common, popular and successful designs: each pair of cylinders has its own separate carburetor.
Like Jaguar, Healey, etc. Ever seen one?
On all three counts, as per the stock set-up, your totally correct. I'd like to elaborate later on some specific reasons why I persist with IR talk.
Recapping:-
In stock form, the log head would not be suitable as an independent runner, you are correct.
In stock form, the Holley 2300 isn't suitable for a IR carb set-up, you are correct. The power valves, over rich jetting, idle air bleeds and the signal from the booster venturis are not even close.
Regards IR, and its cheaper "each pair of cylinders has its own separate carburetor" brother, correct. The real world results are better with a set of well tuned triple carbs if tuning is perfect ( like the irrepresible Stromberg CD and SU set-ups on Holden Torana XU1's, Aston Martin DB6's, DBS, Jag XK-E's, Jensen Healys and Austin Healys).
The specific issue I'm making is that the
1) SU's and CD's don't pulse tune compared to an IR Weber set-up.
2) The SU's and Zenith Strombergs create competant low end torque and mid range torque due to the accelerator jet action of the dashpot/venturi bridge creating a very favourable vaccum gain.
3) They also gain on the ability to residentially map the fuel curve to MAP pressure by tailoring in field spring and needle profiles, far easier than on a Weber DCOE et al. So a well set-up trio of well sized SU's is very hard to beat.
4) The issue is that for maximum power, the Webers and Dellortos and Weber worka-likes gain a huge amount of wide open throttle power, approximately 15% on a back to back basis on an I6.
5) The problem is that of state of tune. All the British SU/Stromberg carbs have a very poor ability to say in tune due to the main jet, bias needle, oil viscosity and fuel bulk density changes. Even the last 240 Z Japanese Hitachi HS 4 versions, and the brilliant SU 44HIF's were very poor at exhibiting constant fuel air mixtures at factory, which is why we see such a huge industry in replacing them. They won't stay in tune for a 50 000 miles of hard running like properly set up Webers and Holleys do.
The power gain on Weber ID's and DCOE's over any SU or Stromberg or three duces, is from the pulse tuning, and that is what the ages old Weber chart defines the ideal sizes.
I've done some Law of Machine logorithmic mathematical models, and its clear that a stock 264 cammed 250 Falcon would probably run pretty good with three 4412's with the power valves blocked. It would need an intermediate ciruit to work properly. I've got a 200 log head with 252 degree cam, and I'd say that the triple 7448 would work perfectly.
My assertion is that when you run stock 4412 or 7448 Holley carbs as an IR set-up, and size them to suit a realistic 3500 to 4500 rpm power peak,
The right mods can sort those things out.
I think the log head is a pretty good base to turn into independent runner. All thats needed is some thing to group 1+2, 3+4, and 4+5. A little epoxy or devcon would do the trick, maybee with a small tranfer pipe mortered in. Divorceing a 2300 between barrel 1 and 2 is easy, mounting it is fairly easy. I'd use three alloy 2300 2-bbl to 2CG Rochester adaptor plates
For the intermediate circuits, great news. The Split 4500 Dominator carbs and a few Barry Grant 4150 850 Cfm carbs have a three stage idle, intermediate and wide open throttle circuit sans powervalve. They fit the 2300. I believe wsaIII is using one on his worked 4412/7448's.
I researched this before I started. Same with the emulsion tubes, there are a few custom ones around, and the hole arrangement for creating percolated fuel is on Weber publications and some Holley custom ones.
As for jetting, its easy. Any Holley jet from 40 to 60 is around, and the 512 etc. close limit jets would be a good place to dial in after the general air fuel ratios are found.
With these few provisos, the Weber tuning logic looks exactly transferable to the Holley.
A
Anonymous
Guest
If you look at the barrel of a 3-circuit Holley it appears that the extra circuit is only another hole reached at a later point in the sweep of the throttle disc. It just has to be connected to some fuel channel. The exact position (inches, and degrees of rotation), size, etc. would have to be empirical but the range isn't too wide - I'd start with the same proportion of the disc rotation the 4500 used and the same size hole as the transition hole. You can always meter the flow with an insert upstream.
The same principle has been used to improve plain barrel carburetors such as the Linkert.
In addition, some Holleys can be retro-fitted with an annular booster cluster made from 4010 etc. parts to replace the existing.
If no clear path from a 3rd circuit hole in the throttle bore to a fuel source in the idle well an external line can be used.
Some of the after-market 41565 metering blocks have emulsion circuit capability, so mods could be done (more $$, less wasted time) without drills.
The same principle has been used to improve plain barrel carburetors such as the Linkert.
In addition, some Holleys can be retro-fitted with an annular booster cluster made from 4010 etc. parts to replace the existing.
If no clear path from a 3rd circuit hole in the throttle bore to a fuel source in the idle well an external line can be used.
Some of the after-market 41565 metering blocks have emulsion circuit capability, so mods could be done (more $$, less wasted time) without drills.
Thanks Kitabel. Concise, factual and accurate. You are brilliantly informed. When the technolgy via literature search is there, we have what amounts to a past precendent which should yield results. I love emperical, anectotal and hard erned published information. I only use what I understand. I love the inspiration that comes from actually understanding what the objectives and then designing something to beat the rules. That's where the fun is.
Both the Dominators and 2300/4150's share the 80 degrees throttle sweep, and the 4500 is pretty much a 4150 with a testoserone over dose.
Well, there you go Anlushac11, the cheater engine. Lets build this bad boy! Your task is to design a welded in but removable roll cage which makes a T-top as stiff as a starched kilt in a John O'Groats bag pipe festival.
Your gonna need it!
Both the Dominators and 2300/4150's share the 80 degrees throttle sweep, and the 4500 is pretty much a 4150 with a testoserone over dose. Well, there you go Anlushac11, the cheater engine. Lets build this bad boy! Your task is to design a welded in but removable roll cage which makes a T-top as stiff as a starched kilt in a John O'Groats bag pipe festival.
Your gonna need it!