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Good morning,
I have started to put my Cleveland engine into pieces. I found that flow cross section of the intake manifold does not fit in size with those of the heads (up to 5mm step). I have attached photos from the heads. Does somebody know those (I was told that they were sold by Hall Pantera in the 80th)? I'm looking for the manifold matching with those heads. Any advice?
Head characteristic
• Intake valve 2.19 Inch
• Exhaust valve 1.71 Inch
• Intake port flow area: 2,07 x 1,68 inch
• Exhaust almost circular with 1.65 inch Diameter

Thanks for any advice or thoughts you might have.

Hartwig

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It looks like you have aluminum A3 heads which have raised intake ports. (They are very desirable).

The following is a post from George.

Cool heads, the A3 heads are possibly my favorite 351C compatible canted valve heads. There are 4 manifolds that were offered by Ford that may be of interest, they are all old manifolds. The original one offered by Ford was cast by Edelbrock & looks like a Torker, but the runners were slightly raised and re-sized as an exact match for the A3 cylinder heads. The manifold was designed for 9.2" deck 351C blocks only. The Ford SVO casting number & part number is M-9424-A331. I have an un-used version of one of these I'd be willing to sell. The second one has the exact same M-9424-A331 casting & part number, but it was cast by Jack Roush Engineering. It is a high rise "spider" type manifold. The runners of this manifold were sized for the smaller C302 cylinder head ports, and need to be port matched for the A3 heads. This manifold was also designed for 9.2" deck 351C blocks only. The third manifold (also cast by Jack Roush) has a slightly changed casting & part number, M-9424-B351. It is very similar to the Jack Roush A331 manifold, but it was designed to fit either 9.2" deck 351C blocks OR 9.2" deck 351W blocks. Like the other Jack Roush manifold, the B351 manifold would have to be port matched to the A3 heads. Finally there is the M-9424-A351 Jack Roush manifold, it is identical to the B351 manifold but it was machined for 9.5" deck 351W blocks. This manifold can be cut down to fit a 9.2" deck block. Either of the last 2 manifolds would work with your 9.2" deck G351 block. All of the later manifolds sold by Ford were designed for Yates C3/C3H/SC1/D3 heads with higher intake ports, and if they could be cut down to mate with the A3 heads at all the flanges and valley rail sealing surfaces may end up being paper thin. Edelbrock also offered some high rise manifolds for Ford's various racing heads, but I'm not versed in their part numbers. I'm sure the Parker & TFC manifolds from Australia could be port matched to the A3 heads, but they're designed for 351C blocks, I don't remember them being offered for 351W blocks. CHI probably has a 3V manifold for 351W blocks that could be port matched to the A3 heads. Finally, I saved the best for last, there's the new Air Supremacy manifold sold by Scott Cook, designed by Darin Morgan, it should be a close match to the A3 heads as well, I think Scott can cast it to fit the 351W block. You may want to give Scott a call. http://www.scmenginedevelopments.com/
one way of classifying intake port height location is to measure from the deck surface (head gasket) to the top edge of the intake port entry, there's still 1 intake pic left in this thread glad I saved the others

http://351c.net/board/index.ph...cation/#comment-3102

here's a Roush A3 manifold, there are not a lot of choices & they'll all be fairly serious race oriented





an option could be to use spacers between the heads & intake manifold to reposition a more common driver friendly manifold to align with the ports in the heads, some matching of the spacers would be needed

or use a complete stack EFI system that suits the heads
I use the A3 heads also. Before I went back to the "Webers", I tried both the tall A331 spider and the "Edelbrock" torker type A3.

In the Pantera, the low torker type is by far the best fit to the car.

Here's what it looked like with the Holley 4779.

Ironically, the Webers are as easy or maybe even easier to plumb to the car?

I personally thought that the original Torker that I had on the Boss 351 in my Shelby along with the 750dp Holley was the most responsive to the car.

That engine had the iron "Boss" heads on it and I never tried or had the Holley Strip intake so I personally can't compare the two.

There's an entire story that goes with that Ford Motorsport A331 (torker) manifold.

Hall and Joh Vermersch both claimed that there were only 100 made. I can't prove that either way. I'm just commenting on what BOTH TOLD ME.

Many have disagreed with that.

What others here probably would agree with is that they are "suckers" to find.

I personally have owned three of them and traded each away for parts of whatever the current project was that I was working on then, so mine are...psst...long gone.

By far that would be the nicest intake to match to those heads in a Pantera.

I will tell you though that the A3 intake port is raised just about 1/4" on top and is just about 5/8" shorter on the bottom.

There is an issue with taking just any manifold for a 4v head and bolting them up to the A3.

The issue? 5/8" of the bottom of the port on the intake will be wide open.
You can fill them with platic aluminum IF you want to risk the epoxy falling out. That really isn't worth the risk to me.

You COULD mate that manifold to that head with spacers. Those spacers would have to be made for you, probably by Price at Price Engineering in Indiana.

He gets about $200 for them. I don't know what the combination you would wind up with as far as spacer thickness? He'd have to run that through his computer program and tell you if he could make them or not?

I think that it would be easier to do with a 9.5" W block though rather than with a 9.2" C block.

Price is on the web. Google him. He will come up.

This is what the manifold looked like on my car back when.

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Another view.

You need an angled spacer for the carb with it in the P car. It WILL NOT fit under the screen although it's a much better fit than the spider is .

I don't have pics of that one on the car but as I recall, the top of the air cleaner was virtually against the roof?

I actually sold the last one I had for $800 I think. You just can't find these things.
You could get a spider for $275-$300 used. Those there are plenty of seemingly?

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will a CHI intake might align to the A3's? I don't remember if the intakes are narrower than factory Ford due to the proprietary cylinder head dimensions but the ports are raised ...

where does early Yates before they changed the bolt pattern fall on A3's?

Yates SVO



Yates C3





again, not for every day use, here's a Yates C3 that's been knocking around on ebay for some time
http://www.ebay.com/itm/Edelbr...AOSw9r1V8vfy&vxp=mtr



and I hate to bring it up but a Procomp manifold may actually work for this application?
http://www.ebay.com/itm/Ford-3...AOSwayZXjbjw&vxp=mtr
quote:
Originally posted by 4V & Proud: will a CHI intake might align to the A3's? I don't remember if the intakes are narrower than factory Ford due to the proprietary cylinder head dimensions but the ports are raised ...

If they are “3V” CHI intakes they are narrower and don’t align well with 9.2 and A3 port
quote:
again, not for every day use, here's a Yates C3 that's been knocking around on ebay for some time

If that’s the E351 intake, it’s port is too tall. Sorry, I don’t speak ProComp.

If you are running A3s on 9.2 deck Cleveland and are interested in the M-9424-A331 Torker style A3 intake I have a number of them. PM me. They do have an angled carb pad as do many/most 351c intakes. They can be run as is or with wedge plate to level the carb in a Pantera.

Best,
Kelly
The A3 heads are nice heads. They were Ford's first aluminum racing heads, replacing the cast iron production 4V heads. They are a historically interesting second step improvement in Cleveland heads (the first step improvement was the D3ZE iron street heads). The difference between the A3 heads & D3ZE heads makes folks scratch their heads to this day, because they don't exhibit a unified concept. One was more in tuned with folks dealing with a 4" bore. The other was more in tuned with drag racers who had access to Bud Moore's large bore blocks (I think Smiler ).

It is possible to make big horsepower with the A3 heads. There is at least one other intake manifold option that I hadn't previously mentioned in the post quoted by EH Pantera (Mark). That is the Scott Cook dual plane manifold. Its a close match.

In this day and age the A3 heads are historic pieces as much as the Cleveland engine itself. The iron 4V heads had 242cc intake ports, un-ported. The A3 intake ports were rated 241cc. So don't think they are "high velocity, small port heads". But they didn't have the big inlet with a ramp ... so the intake ports appear smaller than the 4V ports to a casual observer. The A3 intake ports have a more consistent shape and cross-section, and they are aimed directly at the intake valve pocket. The 4V intake ports were aimed to the side of the valve pocket in an attempt to create "swirl" within the pocket. To sum it up, the intake port of the A3 head is a more basic, "no tricks" intake port. But it is a shorter port with a slightly greater average cross sectional area (~2.9 square inches), i.e. its tuned for about the same rpm or slightly higher. In later years the head was advertised as being best suited for engines of 355 cubic inches or more. Ford introduced another head in 1985, the B351 head, which had slightly smaller 223cc intake ports (~2.7 square inches average cross sectional area) and 2.15" intake valves. It was billed as being optimized for NASCAR engines (358 cubic inches, 4.030 bores).

Other tidbits: the A3 exhaust ports are higher and definitely better performing than the exhaust ports of the iron 4V heads. The A3 heads lack the "high swirl" Weslake/Yates combustion chambers of the later "Yates heads", and the A3 valves are too big for a 4.00" bore (no problem for race blocks with 4.080" or larger bores). But those large valves are part of the historically interesting Cleveland legacy ... and they certainly don't keep the engines from making a lot of horsepower. The big valves are not a deal breaker by any means.

I like the heads, I think that's the best description I've ever offered of them.

For the street the heads are plenty good enough as-is. For racing there are better options (Yates C3, C3H, SC1, D3, both of Blue Thunder's heads, etc). For the street the SCM manifold & Hall Pantera exhaust headers will make a good combination with A3 heads. If these heads were already installed in your car, you probably already have the Hall Pantera exhaust headers. The only thing you need to complete a nice street combination would be a cam with low overlap, LSA in the 112 to 114 range, and your preference in intake manifolds. Large, canted valve engines such as the 351C need wider lsa & less overlap if street manners are being sought. The hot rod world just isn't familiar with these old dinosaur large canted valve engines. But I love them, the 351C, the Boss 302 and the 396 Chevy are my 3 favorite engines from that era ... from my era ... which makes me a dinosaur too.
Last edited by George P
Thanks for all those many comments and I’m still digesting them …..

I have tried to summarize my options, please comment, I might have misunderstood:
1. Edelbrock M-9424-A331
2. Edelbrock torker type A3. Is 1. and 2. the same?
3. Jack Roush Engineering M-9424-A331
4. Jack Roush M-9424-B351 but requires cut down
5. Parker & TFC manifolds from Australia
6. CHI 3V manifold which does not align well
7. Scott Cook dual plane manifold

Which of those manifolds can be purchased with a reasonable budget?

I have Hall Pantera exhaust headers installed. However, the engine is far away from making big horsepowers. It feels like a stock engine and I’m wondering why? Above 4000 rpm the engine feels lazy. Far away from able to get the wheels spinning in first gear.
Yesterday, I removed the camshaft and I found a Howards (seems to be a low budget brand). On the cam shaft I only found the indication “SS I”. I measured the cam and found: Lift at exhaust valve .54; lift at intake valve .48; lobe separation 113; Intake centerline 105; intake duration227@.05; exhaust duration 235@.05.
Any thoughts and advice where to find the missing horses?

Compression rate (CR) of the engine is 10.3 and it was stroked by the previous owner to 371 inch3

Below a picture from my current manifold. I could not find any Part number. It only says Ford MotorSport

Brgds

Hartwig

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quote:
Originally posted by SIG:
From the photo you can see that the manifold cross section does not fit well with the head. There is not enough wall thickness to grind the manifold to the size of the heads.
Brgds

Hartwig


That is the design of the intake. The spider IS NOT the original designed intake for the heads. The Torker style is.

I had the B351 heads as well, and actually the spider manifold was made for them. That is the shape of those ports.

Also, the A3 is the first of the aluminum "high port" heads in this series.

Lots of development has been done off of the original A3 heads but that comes about due to the different requirements of RACING.

None of these are "street heads". Some can be used in street applications. Maybe the A3 are the best examples of that?

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Last edited by panteradoug
That intake (M-9424-A331 Roush Version) was available as cast with either a C302 or A3 sized port window as was the M-9424-A351. They appear nearly identical but are slightly different intakes. The part numbers were the same so how you specified one over the other when ordering, IDK. The race teams usually picked up the phone or told their factory rep I suppose but there were all kinds of variation when it comes to these race parts.

I own the Torker style A331 in both A3, B3, and C302 size ports. The B3 may have just been a C302 version ported to that size but the A3 and C302 units are as cast runners. In fact, for the C302 runner version, I bet I could lifter finger prints and DNA matching several of the people that have posted in this thread.

Unless your A3 heads have been ported wider (than 1.75”), that intake can be ported to match them. 4V & Proud’s post shows the intake with the A3 port window. I can’t say for sure from the picture but the port window dimensions in your first post are pretty much as cast/stock for A3s. Have the decks been milled and do you know the combustion chamber volume? You mention a static CR of 10.3:1 but if it’s stroked I would think you’d need a dished piston or fairly thick gasket to get back down to that ratio.

With all due respect to the 4V purists, IMO the A3 is a better head in almost every respect than an iron 4V head. They are lighter, being aluminum and running a little cooler probably nets you another .5-1 point of safe pump gas compression ratio, the intake ports are (slightly) more energetic and flow better, the exhaust port is way better, and they all have screw in pedestals for adjustable valve train. Possible negatives are no egr if that matters to you, and the threads may not be as durable. In front engine cars with shock towers the exhaust port position is a problem but that is not an issue in a Pantera. They will require a purpose built header which you must already have because a 4v header won’t bolt up to the A3 heads properly.

The biggest issue with A3s is they are 30 years old and have typically been through so many hands and fiddled with so much you don’t know what you have without close examination. Do they still have the original iron valve guides or do they have bronze guides?

I’d be suspect of the whole engine as it appears to be a mish-mash of parts. That intake has been drilled for NOS foggers and slapped on the engine and was obviously worked for another engine. The heads look like they had been running pig rich. With that cam and fact it wouldn’t rev above 4krpm it could be something as simple as carburetion or ignition or it could be something very serious like tired or mismatched valve springs, though if the latter were the case I suspect you’d have even bigger problems to discuss. Is it a flat tappet cam and did you measure those specs or look them up? Are the lobes worn flat? Did you do a leak down test on each cylinder before you pulled it apart. -There's a lot of ground to cover here.


I’d recommend you seek out a Cleveland engine specialist, tell him how you want to use the engine and either have him build it or pay/take his advice on component selection. Even if you are an experienced engine builder there are nuances to every engine.

Take care,
Kelly
Interesting!
• Who knows where to purchase a Torker style A331 in A3 size ports. Could not find anything on the Edelbrock homepage.
• The port window dimensions are cast/stock for A3s and were not ported
• The deck was not milled (I think): I have 64cm3 volume in the head, 8.9 cm3 for the gasket and 8.5 cm3 for the dished piston. Engine C.I.D. is 369 inch3 gives a CR 10,28
• The heads have still the original iron valve guides. They were first installed on my engine by the previous owner who made 5000 miles with it.
• Yes the engine was running very rich. There was a 850 CFM Holly installed. Spark plugs were always dark black and people driving behind my car where mentioning fuel smell. I went to a smaller carburetor which fixed the issue and significantly improved drivability in bumper to bumper traffic but did not change max engine power.
• The engine did 5000 miles. There is no wear on the tappets and cam. Components look like new.
• I did a leak check of the valves. They are all perfect, no leaks at all. Compression was equal and high on all cylinders
• On the ignition: I have a Duraspark box with an MSD distributor. Plugs and cables are new. All spark plugs look excellent (with the new carburetor). Timing is 16 degrees at idle. 36 degrees total.

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