Best way to proceed with improving up 427 Windsor street setup

[Bernica]

IMHO, I wouldn't use a single-plane intake for a street application.

[Ace23]

Originally Posted by Bernica

IMHO, I wouldn't use a single-plane intake for a street application.

I have never been in a cobra with a dual plane and I don't believe any of the local cars to me have a dual plane. I was reading B. Lykins 438 Windsor build where he used a "massaged" RPM airgap and that was pretty interesting. If it is a street car that you are not reving above 6000RPM then maybe the dual plane is the way to go. Before I hauled off and bought another manifold I want to make sure it is the right one. I do not believe a dual plane would match up well with my current camshaft and 2" primary heads so that is something to consider as well. I can' find much information that is based on real world test on primary header sizes on cobras but the few things post I have come across no one was raving about their 2" headers except for higher RPM setups.

[scottj]

Originally Posted by Ace23

... I can' find much information that is based on real world test on primary header sizes on cobras but the few things post I have come across no one was raving about their 2" headers except for higher RPM setups.

What is the reasoning for using 2" primaries in this application? We didn't using anything bigger than 1-7/8" on 440+ cid, 850+ HP, dirt oval race engines... and we had plenty of real world data. Maybe 2" for a drag race application, but drag and street aren't really relatable.

[blykins]

A single plane intake on a big engine is a whole lot different than a single plane on a small engine.

An engine that has enough guts to suck hard enough on a single plane intake will have gobs of power everywhere.

I would go with a Victor Jr....

[Ace23]

Originally Posted by blykins

A single plane intake on a big engine is a whole lot different than a single plane on a small engine.

An engine that has enough guts to suck hard enough on a single plane intake will have gobs of power everywhere.

I would go with a Victor Jr....

Brent,
I will take your advice and stay with the current Victor Jr I have. I saw where your 438W used the dual plane so I thought that may be applicable for my 427W and any future higher CI that I took it to. I have purchased some stainless fittings to dress up underneath the hood and now I need to clean the intake manifold. When I was in high school I used to work at a bike shop and we would bead blast aluminum. Is having the manifold bead blasted the best way to restore the raw finish or do you have a recommendation on how to clean it.

[Ace23]

Originally Posted by scottj

What is the reasoning for using 2" primaries in this application? We didn't using anything bigger than 1-7/8" on 440+ cid, 850+ HP, dirt oval race engines... and we had plenty of real world data. Maybe 2" for a drag race application, but drag and street aren't really relatable.

The headers came on the car when I purchased it. I haven't really looked at what options I have but my initial impression was that 1-3/4" would suffice as that is what most of the cars I have seen have. I'm sure the 2" flow well in high rpm applications but I would think they would be hurting the bottom end.

[Anthony]

A good dual plane will still make good power.

My "stock" 427 FE, (429 ci) with an original 1964 dual plane intake, original style heads, 1965 holley carburetor 3255-1, made about 30-50 more hp and torque than the roush 427R crate motor, with "state of the art" single plane intake, heads, and carb , tested on the same dyno.

[blykins]

I would lean towards that 427R being hurt then.

I've built/dyno'd a few 427FE's with factory parts and they wouldn't touch what a Roush 427R should make by a long shot. A Roush 427R should be in the 525-550 hp range. You're saying that your FE with all factory parts made almost 600 hp?

Not saying you're wrong on what you saw, but logically, that should not be correct.

[Anthony]

Well, I built my engine years ago, but had some coolant leaking problems, turns out I had a bad intake. Had Eric at performance engineering fix my water leak - needed a NOS intake, and then dyno tune my engine.

He told me that he had installed and dyno tuned maybe 20 roush 427r's in superformances, and my engine made 30-50 more hp/torque than the best 427r he had tested.

that's what he told me. He showed my my dyno sheet, and then the dyno sheet from the best 427r he had tested.

does that mean that you are wrong ? :-)

[blykins]

Well, maybe....

Chassis dyno or engine dyno? How much hp did your engine make?

A Roush 427R is basically a Dart block, aluminum heads that flow somewhere around 300 cfm, a hydraulic roller cam, a Victor Jr. intake, and a carb. I do similar combinations all the time and they are always around the 525-550 hp mark. Coincidentally, Roush rates their 427R at 550 hp.

Logically speaking, the displacement is the same, but factory FE head/intake parts are not on the same platform as modern SBF parts, and that's where the difference lies.

Not saying you're wrong, but I think there's a discrepancy somewhere that is being left out. No way a factory 427 will beat a new Roush 427 R (or any 427 Windsor by any manufacturer) by 30-50 hp.

[Anthony]

Originally Posted by blykins

Well, maybe....

A Roush 427R is basically a Dart block, aluminum heads that flow somewhere around 300 cfm, a hydraulic roller cam, a Victor Jr. intake, and a carb. ---, Roush rates their 427R at 550 hp.

Logically speaking, the displacement is the same, but factory FE head/intake parts are not on the same platform as modern SBF parts, and that's where the difference lies.

Not saying you're wrong, but I think there's a discrepancy somewhere that is being left out. No way a factory 427 will beat a new Roush 427 R (or any 427 Windsor by any manufacturer) by 30-50 hp.

Well, a factory 1964 FE crate motor did beat out a modern roush crate 427R, so I guess you are wrong.

Long before Roush and you were building crate motors, Ford was, and around 1964-65 Ford offered a crate 427 Hi-Riser , dual plane, single four barrel I believe rated at 485hp. Don't forget, NASCAR banned Hi-Riser heads from racing. I built my engine to replicate this crate motor.

I built my motor to replicate this engine, with an original intake from 1964, original Holley carb that came on that motor, and original pattern aluminum 1964 Hi-Riser heads from Dove. 1968 427 service block bored 0.017" over, cast crank. Actually, I believe there was literature from Shelby that you could have gotten this motor as an option for your 427 cobra, although I'm not sure how many, if any did, although I know a couple cobra's came from Shelby with Hi-Riser heads.

So, my 1964'ish Ford crate 427 did out perform a modern Roush 427R motor. I guess the Ford engineers back then knew a little?

[blykins]

Well, a few things we still need to point out....

1. 485 hp is a far cry from 525-550. I agree, that's a reasonable estimation for a 60's period FE. I built a 427 FIA road race motor, using C3 LR heads, and a 2x4 LR intake. Both had been heavily ported. Compression ratio was 11.5:1, cam was a large solid flat tappet. It made 510 hp.

Even 510 hp is a-ways off from 525-550.

2. We don't know what your engine made, or how it even relates to what Eric had told you about the dyno sessions. There is/was a miscommunication somewhere if you think your engine is making 575-600 hp.

I'm not calling you a liar. I'm not calling Eric a liar. I'm just saying that a factory 427FE will not make 525-550 hp (which is what the Roush 427R is rated for, and what we commonly see from typical 427 ci Windsor builds), much less make 30-50 hp MORE than that.

So, if you're going to make that claim, I would want to see more information and proof. Until then, we can all hold hands, sing "Kumbaya", and talk about what Ford did in the 60's...

[Bernica]

A long time ago I think I got close to around 550hp with a Tunnel Port using all the old Ford Muscle parts, but it was not street friendly at all.

[blykins]

Love the Tunnel Ports.....

Last 3 I've done made 580 hp, 696 hp, and 722 hp....

I still think there has been a break in communication somewhere. I know that Eric has a chassis dyno there, and to me, there would be little reason to pull (20) Roush 427R's out of the crate and put them on an engine dyno before installing them into Cobras.

My gut tells me that the info that has been provided above has all been chassis dyno stuff, which opens a whole other can of worms, and a whole other can of variables.

Would like to see the dyno sheet.

[1985 CCX]

Webers............��

[Ace23]

We got the brakes bled and everthing back on the car and buttoned up. The brake fluid really needed changing.....it looked like jet black motor oil!. We fired up the car and checked for any oil and gas leaks but none were found. We allowed the engine oil and water temp to reach operating temperature and then we checked the timing. What we found was that the timing did not fully advance until about 3500-3700rpm. The distributor cap was checked and it was found to have two of the heavy silver springs. We changed one of the springs to a lighter tension spring allowing full advance in about 3000rpm. We did not make any timing adjustments as the timing was previously set when the car was dyno tuned leading to the low numbers which sent me down this path. We plan on taking the car out for a test ride tomorrow to see if any improvements is seen. I'm still not ruling out a cam change and leak down test but the car needed some general mainteance and I wanted to eliminate a few things off the list. Big thanks to PMAN1961 for all the help and teaching me the ropes on these cars!

[RET_COP]

Sounds like you put a light silver in. Good move, go quicker and try two blue springs, light stick shift cars like the cobra respond well to this advance curve. Going in the right direction, good luck!

[blykins]

X2....

Most performance applications in general respond very well to a quick timing curve. I would set the total timing to be all in by about 2600-2800.

[Pman1961]

You are welcome ACE!! Thanks for not telling all I crossed a pair of wires on the distributor cause a nice little pop at our first crank!! Brent I agree with the earlier full timing. Again, the Internet provides so much advice not all being the same which makes making decisions difficult. The tuner and an article I read recently recommended full timing at 3000 on this size stroker engine. We can swap some springs no problem to achieve the specs you are suggesting.

[Ace23]

Originally Posted by RET_COP

Sounds like you put a light silver in. Good move, go quicker and try two blue springs, light stick shift cars like the cobra respond well to this advance curve. Going in the right direction, good luck!

That is correct. The cap had 2 heavy silver springs and we changed one to the lighter silver spring. This resulted in full advance coming in at around 3000rpm compared to the previous 3500rpm. Thanks for the advice

Originally Posted by blykins

X2....

Most performance applications in general respond very well to a quick timing curve. I would set the total timing to be all in by about 2600-2800.

As Perry noted we can change to the 2 blue springs and see where that gets us. I do have a question as I do not completely understand timing and what effects it can have. If we changed the springs and full timing comes in 2600-2800 what happens when you are cruising on the interstate at 2500-3000rpm? Is it a bad thing to be at a cruising speed with full advance? I do not want this to be about gas mileage but will I see any improvement if I am running the lighter springs and my timing is more advanced at a lower RPM state?



I did find this write up and just thought it was interesting.

TIMING AND VACUUM ADVANCE 101

The most important concept to understand is that lean mixtures, such as at idle and steady highway cruise, take longer to burn than rich mixtures; idle in particular, as idle mixture is affected by exhaust gas dilution. This requires that lean mixtures have "the fire lit" earlier in the compression cycle (spark timing advanced), allowing more burn time so that peak cylinder pressure is reached just after TDC for peak efficiency and reduced exhaust gas temperature (wasted combustion energy). Rich mixtures, on the other hand, burn faster than lean mixtures, so they need to have "the fire lit" later in the compression cycle (spark timing retarded slightly) so maximum cylinder pressure is still achieved at the same point after TDC as with the lean mixture, for maximum efficiency.

The centrifugal advance system in a distributor advances spark timing purely as a function of engine rpm (irrespective of engine load or operating conditions), with the amount of advance and the rate at which it comes in determined by the weights and springs on top of the autocam mechanism. The amount of advance added by the distributor, combined with initial static timing, is "total timing" (i.e., the 34-36 degrees at high rpm that most SBC's like). Vacuum advance has absolutely nothing to do with total timing or performance, as when the throttle is opened, manifold vacuum drops essentially to zero, and the vacuum advance drops out entirely; it has no part in the "total timing" equation.

At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15 degrees of spark advance, on top of the initial static timing setting (i.e., if your static timing is at 10 degrees, at idle it's actually around 25 degrees with the vacuum advance connected). The same thing occurs at steady-state highway cruise; the mixture is lean, takes longer to burn, the load on the engine is low, the manifold vacuum is high, so the vacuum advance is again deployed, and if you had a timing light set up so you could see the balancer as you were going down the highway, you'd see about 50 degrees advance (10 degrees initial, 20-25 degrees from the centrifugal advance, and 15 degrees from the vacuum advance) at steady-state cruise (it only takes about 40 horsepower to cruise at 50mph).

When you accelerate, the mixture is instantly enriched (by the accelerator pump, power valve, etc.), burns faster, doesn't need the additional spark advance, and when the throttle plates open, manifold vacuum drops, and the vacuum advance can returns to zero, retarding the spark timing back to what is provided by the initial static timing plus the centrifugal advance provided by the distributor at that engine rpm; the vacuum advance doesn't come back into play until you back off the gas and manifold vacuum increases again as you return to steady-state cruise, when the mixture again becomes lean.

The key difference is that centrifugal advance (in the distributor autocam via weights and springs) is purely rpm-sensitive; nothing changes it except changes in rpm. Vacuum advance, on the other hand, responds to engine load and rapidly-changing operating conditions, providing the correct degree of spark advance at any point in time based on engine load, to deal with both lean and rich mixture conditions. By today's terms, this was a relatively crude mechanical system, but it did a good job of optimizing engine efficiency, throttle response, fuel economy, and idle cooling, with absolutely ZERO effect on wide-open throttle performance, as vacuum advance is inoperative under wide-open throttle conditions. In modern cars with computerized engine controllers, all those sensors and the controller change both mixture and spark timing 50 to 100 times per second, and we don't even HAVE a distributor any more - it's all electronic.

Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it.

If you look at the centrifugal advance calibrations for these "ported spark, late-timed" engines, you'll see that instead of having 20 degrees of advance, they had up to 34 degrees of advance in the distributor, in order to get back to the 34-36 degrees "total timing" at high rpm wide-open throttle to get some of the performance back. The vacuum advance still worked at steady-state highway cruise (lean mixture = low emissions), but it was inoperative at idle, which caused all manner of problems - "ported vacuum" was strictly an early, pre-converter crude emissions strategy, and nothing more.

What about the Harry high-school non-vacuum advance polished billet "whizbang" distributors you see in the Summit and Jeg's catalogs? They're JUNK on a street-driven car, but some people keep buying them because they're "race car" parts, so they must be "good for my car" - they're NOT. "Race cars" run at wide-open throttle, rich mixture, full load, and high rpm all the time, so they don't need a system (vacuum advance) to deal with the full range of driving conditions encountered in street operation. Anyone driving a street-driven car without manifold-connected vacuum advance is sacrificing idle cooling, throttle response, engine efficiency, and fuel economy, probably because they don't understand what vacuum advance is, how it works, and what it's for - there are lots of long-time experienced "mechanics" who don't understand the principles and operation of vacuum advance either, so they're not alone.

Vacuum advance calibrations are different between stock engines and modified engines, especially if you have a lot of cam and have relatively low manifold vacuum at idle. Most stock vacuum advance cans aren’t fully-deployed until they see about 15” Hg. Manifold vacuum, so those cans don’t work very well on a modified engine; with less than 15” Hg. at a rough idle, the stock can will “dither” in and out in response to the rapidly-changing manifold vacuum, constantly varying the amount of vacuum advance, which creates an unstable idle. Modified engines with more cam that generate less than 15” Hg. of vacuum at idle need a vacuum advance can that’s fully-deployed at least 1”, preferably 2” of vacuum less than idle vacuum level so idle advance is solid and stable; the Echlin #VC-1810 advance can (about $10 at NAPA) provides the same amount of advance as the stock can (15 degrees), but is fully-deployed at only 8” of vacuum, so there is no variation in idle timing even with a stout cam.

For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum. Absolutely. Positively. Don't ask Summit or Jeg's about it – they don’t understand it, they're on commission, and they want to sell "race car" parts.