I spent hours this evening looking for a picture of a Man-A-Fre 4 carb intake for an FE to no avail.
Then after almost falling asleep again it hit me.

If you had 4 carbs and 4 small plenums with two cylinders each all would have nice pulse seperations except #7 and 8 which fire in sequence.
Perhaps that is why the XE numbered dual quad Tunnel Port intake I used to have had a divider cast across the back seperating #4 and 8 from the rest of the plenum?

Maybe the ideal intake needs to find a way to isolate #7 from #8? Perhaps this is why a dual plane sometimes doesn't cost much power even though half it's ports have a bad head entry angle?

This is a quick thought with no research so hopefully it won't get me into trouble in here...or maybe this is old news to the hardcore racers. Has anyone tried a custom camshaft with a different firing order like Ford did with the small block HO engines? 15426378 changed to 13726548. Could this work with the FE? If so, could this help correct the cylinder balance problems between 7 and 8 by changing the valve event timing?

Dave Walters
427 Galaxie Registry
Website
http://home.ptd.net/~pwalters

problem to the front 2 cylinders. It becomes 6 then 5 instead of 7 then 8.

with no research. Then I guess this was just done to help eliminate the problem with crossfire between 7 and 8.

Dave Walters
427 Galaxie Registry
Website
http://home.ptd.net/~pwalters

The change in the firing order helps with crankshaft twist and flex, reducing it somewhat as compared to the standard firing order. So, it will provide some HP improvement, as well as better longevity for the crank.

Jay Brown
1968 Shelby GT 500 Convertible, 492" 667 HP FE
1969 R code Mach 1, 490" supercharged FE, 9.35 @ 151.20, 2007 Drag Week Runner Up, Power Adder Big Block
2005 Ford GT, 2006 Drag Week Winner, 12.0 Daily Driver
1969 Ford Galaxie XL, 460 (Ho Hum....)
1964 Ford Galaxie 500, 510" SOHC

The 4 deuce intakes for FHs had one hole from each Stromberg directly over each intake port. They were not manifold free ("Man-a-free"), but the plenum was pretty much just a balance tube. Old tests showed that the strategically place four 2 barrels was within a fraction of being as efficient as 8 port fuel injection.

Hollis Franks

Black 63 1/2 XL R Code

Gray 65 289 Falcon Ranchero

thanks for the input on that Hollis.

Jay, has anyone that you know of tried rearranging the firing order on an FE like Hollis posted? If this would work it could have two benefits. Better engine harmonics and better airflow distribution in the intake. Both of which could increase horsepower.

Dave Walters
427 Galaxie Registry
Website
http://home.ptd.net/~pwalters

- sequential firing to 2-1. You can never get rid of it. All V-8 firing orders have this problem.

Bob

1966 7 Litre Convertible
1959 F-100 (under construction)
2005 GT40 (in my Dreams)

Although many claims are made for why this swap works and gains hp, having raced BBC's (sorry!) long ago, I believe the gain is all in the cylinder filling area. By separating the intake stroke of adjacent cylinders, they no longer steal or share the same air/fuel charge. This phenomena would only occur with a common plenum intake (single or dual plane, many tunnel rams). Have always wanted to find someone running a non-plenum intake (old school mech. F.I. system, a modern EFI system with I.R. stacks, etc.) and see if nay gain was noticed. I'll bet a few $ not!

See Lunati's details:

Memphis, TN--LUNATI, The Racers Company, is proud to announce the availability of their new line of 4/7 SWAP Camshafts for small and big block Chevrolet solid roller applications.

The 4/7 firing order SWAP configuration decreases crankshaft deflection, delivers a smoother torque curve, and aids acceleration. 4/7 SWAP Camshafts also provide an incremental horsepower gain in the engine. 4/7 SWAPS were track tested in a wide variety of applications and all results were improvements over the standard firing order. Dyno results have shown a 3 to 12 HP gain with the SWAP. The only change that must be made to the engine is to swap the 4 and 7 plug wires to reflect the alternate firing sequence. 4/7 SWAP Cams are available in most popular grinds and on custom ground camshafts.

Whats the SFO?* -* What some camshaft grinders are touting as a new development in technology, is old news at Crane.* For over two decades now, Crane has offered SFO cams for many popular V8 engines. What's SFO?* That's Special Firing Order.* It's what many folks refer to as 4-7 firing order swap camshafts (1-8-7-3-6-5-4-2).* Many Chevrolet 262-400 V8, Chevrolet 396-454 V8, and Chrysler 426 Hemi V8 2.125" journal diameter finish ground camshafts with SFO, are offered on Crane in-house manufactured 8620 and 9310 steel billet carburized cores. This is at no additional charge from standard firing order versions!* Custom round lobe blank camshafts can be produced for most other V8 engine applications.
*
The 4-7 swap firing order can help intake manifold distribution inequities, reduce the load on the rear main bearing, and perhaps gain torque and horsepower in certain RPM ranges. Although some drastic claims have been made for this modification, a power increase of 1 to 2 percent is realistic in some situations. No machining is necessary, just slide the cam in, swap some spark plug wires, and there you go!
*
The 4-7 swap appears to be most beneficial in multiple carbureted and large cubic inch single carb applications.* For folks limited to one "small" four barrel, we can produce SFO1 firing order camshafts (1-8-7-2-6-5-4-3) on special order. Many racers use this as their secret weapon in Super Stock type engines.* Some folks might recognize this as the Chevrolet LS1 type firing order, while the Ford enthusiasts might note that it's the 351W firing order when renumbered to the Chevy layout.
*
There are many other firing order combinations that can be produced for special applications. We've even done some "Big Bang" applications, where two cylinders are fired at once, but that's another story.

I just went to the web and typed in "chevy 4/7 swap", for these. There are many others if you would like more information.

Thanks...it seems like some of the racers in here are keeping quiet on this post...lol! Might be worth while looking into.

Dave Walters
427 Galaxie Registry
Website
http://home.ptd.net/~pwalters

it's easy enough to do IF one gets a cam grinder to custom cut a Ford FE cam blank.....just tell them which cylinders to swap!

This old trick (about 20 years now) was first developed IIRC by G.M. Pro-Stock racers. To my knowledge (limited, to say the least!) it was used for quite a few years in secret until it became common knowledge. I've often wondered if even Stock class BBC racers used it since no rules exist to prevent it's use...whether Pro Stock or Stock, every single hp helps!

But, I wasn't kidding in my prior post. I do not see then or now why this change (especially for the cost of a special cam!) makes ANY hp or torque difference in a BBC or BBF unless they have a common plenum. Yet, it does!

Here's my take again: In common plenum intakes, cylinders that 'fill' adjacent to one another before firing aren't being fully fed (or loaded) since the valve opening/closing events are too close together. Going back to my premise, a I.R. (independent runner) intake, be it old school Hilborn/Enderle/Lucas mech. F.I., Weber's, etc. should be totally unaffected by the std. Chevy or 4/7 swap firing order. So, if improved cylinder filling is the reason why it works, perhaps it could work on a FE.

Some other thoughts include rpm range. Methinks this cylinder switch has virtually no effect at idle, lower and even mid-range rpm levels. The engine's intake pulses at these rpm level may be low enough to allow 100% or let's say near ideal cylinder charging. Perhaps only at very high rpms (I've no proof of this, btw) does the air/fuel mix in the plenum run out of 'time' to charge adjacent cylinders.

Below is a somewhat current R-M article worth remembering. Tod bad it's Chevy oriented and not FE but virtually all concepts transfer anyway:

http://www.chevyhiperformance.com/tech/engines_drivetrain/complete_builds/0608ch_race_engine_building_tips/index.html

I did note that Barry R had relocated his FE's heads (via repositioned locating dowels) on the recent Engine Masters buildup. By doing so , he better centered the valves on the rounder (center) part of the cylinder bore, thereby increasing flow near the edge of the valve seat. See, it's the net gain from these kind of modifications I'd like to see more of here for the old FE.

Some more examples that I'd love to see dyno documentation on include:

-heavy angle milling of the heads to tip up the intake ports, providing a better shot at cylinder filling, plus easier gains in compression.

-the offset of the heads (ala' Barry R) to determine the best positioning on the block's bores.

-doing the 30 year old+ Hi-Port Ford Cleveland Pro Stock mod to a pair of FE Heads, TP's in my thinking. Machine away a goodly chunk of the head, bolt on a thick aluminum plate and relocate the exhaust roof at least 1" higher than current. The elimination of the L-R orientation of the std. exhaust ports should alone pickup hp and even out an exhaust flow issues.

-use 1" lifters, a larger base circle cam and near 1" lift in a max. effort FE to see the effect of zero deflection in a modernized valve train.

Ah, nice to dream, eh?

After digging a little deeper into this it seems that cubic inch, plenum size and, runner length have a lot to do with the success of the firing order swap. The larger cube engines running multiple carbs and a tunnel ram or sheet metal intake seem to benefit from it more. I think that it could possibly cut down on intake reversion and help with engine harmonics. Intake reversion could really play a big part in it especially with large overlap camshafts. Maybe the intakes with the larger plenums are more greatly effected by this since the carb signal is further away from the entry area of each individual runner?

In some of the reading I was doing about this it made mention that the crankshaft builder basically dictates the firing order which makes sense. Who better to decide how the valve events occur than him!

I like your suggestions about the dyno comparisons. The ideas themselves have been out there for quite some time but have they ever been applied to the FE engine? Maybe Jay or Barry know those answers.

Losts of food for thought thats for sure...

Dave Walters
427 Galaxie Registry
Website
http://home.ptd.net/~pwalters

The 351W and 302HO are the same as the "new" LS1-2-6 GM firing order. The Flathead and Y block to me are the best, but if you look at the pattern, either the FH or the 351W loads the crank more evenly crossing the bulkheads in an X rather than hitting the same rod throw twice insequence than the FE/ 3021/ "old" GM/ Mopar one. At the speed air is moving in an intake, once they are up to speed, I think you are really just moving the distribution problem around. There will pretty much always be two hitting side by side on the intake. The cure is a dual plane to isolate the resonance for the whole range. A single will always be unbalanced to a degree, but with the right circumstances the resonance can still be effective in a more limited range.

The idea seems more suited for paired intake ports. FE's would need 8 small carbs. The CrossBoss Autolites were used to do this on small block Fords.

Tom, did you ever do anything w/the 61 wgn?
Ron.

I still don't even have the damn thing home yet. The guy is no hurry to find me the regi so i'm not rushing to get his van running (I supply a 302 for it)