WANTED : 8 Stack suit 302 Windsor

Webers or EFI?

EFI but will look at webers. Please PM me

I have a Weber 48IDF setup for a 302, has a vacuum plenum on the underside and a bleed crossover installed.

As you are in Australia you might consider an AussieSpeed manifold  and get a set of ITB's to mount on it. https://www.aussiespeedshop.com/quad-weber-manifolds/

Does such an intake like the one from aussiespeed with a sharp turn and very short runners really make sense on a 4V Headed Cleveland?

@GeorgS posted:

Does such an intake like the one from aussiespeed with a sharp turn and very short runners really make sense on a 4V Headed Cleveland?

I think it depends what your ambitions are for the motor. The Aussiespeed manifold is a 2V, but with enough material to port match to 4V. One advantage for Pantera owners is that you can mount 48IDF carbs with filters or stacks and have it all fit under the engine screen and no cutting of decklid.

They will all work but some systems will work better then others. It all depends on what your definition of better is. Not someone else's.

No shit Sherlock!

Please don't be offended, I couldn't resist. Sorry

My theory (and the reason for my question) is:

On a 4V headed street driven engine, these short runners will make less torque low and midrange, so it is more useful with a big cam that focuses on the Highend Power.

Big Cams mostly come with a lot of overlap which leads to a lot of reverse flow through the short runners, which the Webers don't like, correct? (this is just hearsay for me, I have very little Weber experience) This would make low and possibly midrange even worse.

So this all leads to a high revving racy application, but if so: why would you care if it fits under the stock screen?

So, I hope there are some flaws in my Theory, otherwise I simply don't get it.

Webers worked fine on factory Group 4 Panteras and as options for the Gr-3s for Euro hillclimbs, not to mention the Ford GT-40s..... they are a pain to jet and synchronise correctly. My neighbor Jules' set are probably adjusted pretty close and IMHO nothing looks more trick.

@GeorgS posted:

No shit Sherlock!

Please don't be offended, I couldn't resist. Sorry

My theory (and the reason for my question) is:

On a 4V headed street driven engine, these short runners will make less torque low and midrange, so it is more useful with a big cam that focuses on the Highend Power.

Big Cams mostly come with a lot of overlap which leads to a lot of reverse flow through the short runners, which the Webers don't like, correct? (this is just hearsay for me, I have very little Weber experience) This would make low and possibly midrange even worse.

So this all leads to a high revving racy application, but if so: why would you care if it fits under the stock screen?

So, I hope there are some flaws in my Theory, otherwise I simply don't get it.

The design of the Weber manifold for the 351c was done originally for Ford by Holman-Moody on Detomaso's behalf.

As it turns out, the significant factors for that engine and the individual runner design are the distance from the throttle opening to the intake valve and the opening of the throttle creating a straight line to the intake valve.

That required the throttle opening to be on the intake valve side of the intake and the distance from there to the valve being 4.5 inches.

You can also add the optimum diameter of the runner for the 351c at 51mm.

That is what was described as "maximizing" the design. That was for the best overall torque, horse power and throttle response.

Those numbers do not vary much from engine to engine since it is the characteristics of the carburetor that effect the variables the most.

As it turns out, probably co-incidentally, that the 9.2" Cleveland just happens to work out very well with the space available for carburetor location.

Smaller engines like the 8.2" Ford 289 are not quite as good although still very responsive.

The 427 Fords have issues with the entire set up. For one thing, the displacement would ideally require 58mm throats and the Webers for those, although in existence from the Ford Indy program, do not have an ideal venturi ratio, thus the engine is not responsive enough using the 58's.

You might think that this is all trivial but when you run all of these combination you can see the difference in just reversing the carbs in relationship to where the throttle opening is to the intake valve.

One of the solutions to simplifying the throttle linkage on Ford V8's with the Weber 48ida set up is to reverse one bank of carbs so that the linkages are in parallel and therefore not need a the center pivot.

That absolutely works for the linkage put does noticeably affect how the engine responds and it simply is not as responsive to the instant throttle openings.

That is as much an idiosyncrasy of the individual runner design of the manifold as anything.

Interestingly enough EFI conversions are not as susceptible to the response change because of the CPU's involvement in controlling the fuel injectors.

Additionally, comparing single 4v inductions to individual runner intakes makes no sense because they just do not work the same way. There is no single plenum on an IRM. You get reversion, or reverse pressure in it which reverses the flow of the atomized fuel and pushes it out of the stacks.

A single plenum uses that pulse to push the fuel into the next cylinder.

One thing that is similar would be the ideal length of the runner though, but even on a Wieand tunnel ram for a Cleveland, the distance from the throttle opening to the intake valve is much longer then 4.5 inches.

All of the IR manifolds work. Some just work differently or better then others, but in many case better might just mean 5 more hp at 7,000 rpm?

To ask for further clarification is as Commander Scott once said, "you remind me of the man who demanded to be told the wisdom of the world while standing on one foot". It kind of doesn't work that way.

There is also a split 8-stack Weber intake that uses a valley cover. They're sensitive to throttle linkage routing, whether carbed or EFI. One friend  had EFI on such an intake pair and it was subject to idle creep when hot. The cold idle was 900 rpm but when it warmed up, the idle always crept up to about 1200 rpm.

On a dyno, someone finally found that the two banks of EFI throttle bodies were linked by rods, heims  and  a bellcrank in the valley. With aluminum heads when hot,  the two heads (and intakes) expanded away from each other enough to pull on the linking rod connections, which increased the idle by about 300 more rpms.

He had to figure out a different method of linking the two sets of throttle bodies using cables..I think the original linkage would have done the same with carbs, on those heads. Iron heads apparently don't expand that much. An aluminum block would likely be worse. Fun with 8-stacks....

Yes, the idle creep problem is worse with an aluminum block. Luckily, technology has solved that particular problem. It’s called drive-by-wire and it allows precise idle speed control. I was sceptical until I experienced it for myself. Even with an IR intake on an aluminum block, my idle RPM stays exactly where I set it.

@bosswrench posted:

There is also a split 8-stack Weber intake that uses a valley cover. They're sensitive to throttle linkage routing, whether carbed or EFI. One friend  had EFI on such an intake pair and it was subject to idle creep when hot. The cold idle was 900 rpm but when it warmed up, the idle always crept up to about 1200 rpm.

On a dyno, someone finally found that the two banks of EFI throttle bodies were linked by rods, heims  and  a bellcrank in the valley. With aluminum heads when hot,  the two heads (and intakes) expanded away from each other enough to pull on the linking rod connections, which increased the idle by about 300 more rpms.

He had to figure out a different method of linking the two sets of throttle bodies using cables..I think the original linkage would have done the same with carbs, on those heads. Iron heads apparently don't expand that much. An aluminum block would likely be worse. Fun with 8-stacks....

I've had that problem as well on my first run at the Webers. I've also heard this mentioned before BUT I have come to the conclusion that it isn't the heat expansion that causes it.

What happens is that you have to find where the linkage is "zeroed". This takes a bit of experience and if you are building your own first linkages, at least three or four variations before you find the one that lets the carbs return to zero on a hot engine.

One of the things overlooked to a good extent is that the carbs or efi tend to act as heat sinks. When you shut the engine off it rises up first just to boil and percolate the fuel out of the bowls all over the engine and often down into the intake runners.

You can't just use the paper gaskets supplied with the carbs or the o-rings with the efi's, you MUST use the thick asbestos gaskets which reduce the heat rising (not all because of the carb studs transfer some) but also prevent the carbs from walking on the manifold pushing on the linkages.

This isn't a simple thing to do and if you are even a bit  schizophrentic tending your mind will run wild with conspiracy theories and you will just slip helplessly into psychotic episodes which will preclude you from further dabbling in Webers or the like.

This was all seemingly proprietary information when I decided to take the plunge in the late '70s on this. The only help there was, was Jim Inglese and he was in the learning lane as well.