Single 4 Intake

[My427stang]

Did they have their own line of intakes?

Doesn't look like an F427 at all, and enough differences from a 428PI (although closer) to say they aren't that either

Neat intake

[thatdarncat]

Kevin, on that HM intake what are the 4 small tabs next to the VC rails used for?  One of them has a small pan head screw in it. I've never noticed that before. Thanks.

I don’t know what the purpose of the tabs are, but they’re actually on most original Ford FE aluminum intakes, or the Ford based ones like that H/M. The tabs are on that ‘60 352 HP intake, they’re on these M/R & P.I. intakes, and they’re even on this SOHC intake. Maybe Jay can comment if he thinks they serve a casting or machining purpose. What’s noticeable on that H/M intake is that they’ve been drilled.  I don’t know if there was a purpose for the drilled holes? I bought that intake at a swap meet about 35 years ago and that’s how I got it.

[427John]

Did they have their own line of intakes?

Doesn't look like an F427 at all, and enough differences from a 428PI (although closer) to say they aren't that either

Neat intake

Back then Ford and Holman Moody were such a cooperative effort it was hard to tell where one ended and the other began.The intakes were cast at the same places and in some cases such as some small block intakes they had intakes that were nearly identical sporting different logo's such as Shelby,Ford,Cobra,Tiger,and H/M.There were examples of parts being branded from one source and not the other,but Fords full line of performance parts were available thu H/M.

[jayb]

I think Joe is correct on those tabs, it looks like they are used to index the raw casting on the machining fixture, while leaving other surfaces open to be machined.

[Drew Pojedinec]

I always figured they were for the prybar to get the valve covers off

[wowens]

I always figured they were for the prybar to get the valve covers off

Me too ! They do come in handy !

[427John]

Something that appears to be consistent on the C5HM intakes that typically aren't seen on unmodified Ford intakes is the 3 barrel notch on the plenum divider,the time frame is about right for the introduction of the 3 barrel.The earliest 3 barrels were seen on Mopar 426 track hemis with Lemans bowls and I don't think Mopar had the same exclusive deal for a year that Ford had with Holley when they supposedly subsidized the development of the Dominator.The 3 barrels appeared to be available to all the manufacturers almost immediately.

[frnkeore]

Well, back to this 390 intake.

After posting this, I bought Jay's book (got it in just 2 days ) and it looks like this intake will be a good option for the engine, I'm building. It's a 361 Edsel Block, bored .040, with a Eagle 428 crank. It will have the machined original, machined combustion chambers, too so, a 419 ci engine. A little smaller than the 410 hp, 433 in the book and the 410 hp engine, is right where I want my tq & hp, to be for this mild, everyday type driver.

Comparing average, 2500 - 5300 rpm hp for unported intakes, this intake gives 429 tq & 317.4 hp. With a 382.1 max hp. It's comparable to the 390 Performer's 432.5 tq & 319.8, 379.9 max. It's down 3 lb tq & 5 hp, to the RPM Performer, 6 & 6 to the street Master, almost dead even, with the C4 manifold and beats out, the PI manifolds 426.8 tq & 317.2 hp even, the Ford Tri Power's 422.5 tq & 314.8 hp. The holley Street Dominator, had really good numbers though @ 438 tq & 326 hp.

I didn't think the SM & SD would give as good of low rpm tq as they showed and maybe below 2500 they aren't a good option. I had always heard they weren't a good low rpm manifold. I used to have a SM but, sold it years ago. I always liked the design for a single plane.

Something that I was surprised at though, was the lack of tq at 2500 compared to the SM and C4 both had 19-20 more tq than the 390. I don't understand that, at all.

This manifold has been severely ported in the plenum, all hand work and a little crude so, I set it up and bored the 4 corners to 1.75" diameter and milled the divider straight, to the floor. I think this should raise the upper curve and maybe max hp by ~10 hp? I would like opinions on how they stepped the divider. Will it be a problem?

I will be trying 2 carbs on this manifold, both 4160's. One is a standard 3310-3, 750 cfm and the other is a fairly rare, Mopar 4218, 725 cfm with 1 9/16 primary and 1 3/4 secondary throttles, not a spread bore though. It's one of the reasons I bored the manifold to 1.75, the other to have a clean, symmetric plenum.

I would also like opinions on how much of a radius to put on the runner corners, out of the plenum.

[WerbyFord]

Thank you, all.

I don't have it in my hands yet, it's being shipped so, I can't tell what other porting it's had done, besides the rough looking carb pad. This is a picture of the top. I got it for a  mild (224/230 FT) 410 I'm building.

How did it fare in Jay's tests?

Dont misunderestimate that 390HP intake on a tall-geared car!
I did a GTECH shootout of 4 intakes:
Ed RPM
428PI
390HP
Z-iron LoRiser

Engine was a 434CID, CJ heads, shorty iron, 427-8v cam and also Comp 270S (ie 427-4v) cams.
Tall dog: 4400 lb curb, stock stall c6, 3.00 gear. No tire smoke, but very consistent launches with a couple extra truck tires in back.
Up thru 330ft and 60mph, the 390HP intake won both shootouts. I was surprised. Loses a little on top but lots of low and midrange with a stock 1" 4hole spacer, which made it the same height as the taller intakes.

[frnkeore]

Someone wanted to know what this 4218 carb looks like.

No opinions on the overall plenum, divider or the radius into the runners?

[GerryP]

Someone wanted to know what this 4218 carb looks like.

I had a friend give me one of those off his Dodge Charger 383 car.  He never could get it to run right.  Neither could I.  Ended up putting an AFB on it.  I'm sure they worked fine before nuckleheads like myself got ahold of them.

[pbf777]

No opinions on the overall plenum, divider or the radius into the runners?

     Be more aggressive on the transition radius of the vertical plenum bores in transition to the horizontal port runner roofs, if the material sum is there.       

     Scott.

[frnkeore]

Thank you, Scott,
There seems to be plenty of meat on both the upper and lower runners, to do that, although getting to the back side of the lower runner, will be hard to do. I was hoping for a ball park radius to try to try to attain.

Should I make the rest of the divider, all one height?

[Joe-JDC]

I will go against the current marketing of dividers, and say that if it were my intake, I would fill in the divider and blend everything with good radius into the ports.  You will have fuel distribution problems with making that slot wider, and turbulence into the upper plane for all rpm but all out WOT.  You will also lose some bottom end torque.  BTDT on the dyno, and every time there is a weird curve in the torque as it hunts for clean airflow.  Joe-JDC

[cammerfe]

I was in the shop with John Corrunker one night several weeks after we took delivery on the 'one-of-the-first-dozen' '68 CJ Mustangs. Jack Roush and Al Buckmaster from 'Triple E' came in, bringing with them a then brand new Sidewinder manifold. It was newly machined and had been cast in the little experimental Foundry close by Gate 4 at The Rouge. It didn't have any markings at all on it, as I remember, except the firing order which was in front of the carb mount pad on top of the runner.

We were told that it was intended for a 427, but with some rework it would be significantly better than the factory-installed piece. And lighter too.

We were to add metal at the bottom inner sides of the runners so as to have enough metal to cover the ports at the gasket interface.  And, since we were running a C6---the car was a Super E Auto---the missing fore-'n'-aft divider would have to be filled in. As cast, the manifold was intended for a stick car.

The plenum, as delivered, looked very much like what is pictured above.

John had most of the work done, but by the time we got it back, it had been found that something else was better for class racing, and it went on a shelf to gather dust.

The better part of a year later, I put a 427 together to go in my '67 Cougar XR7 GT. John knew I was scrounging for some of the parts, and he offered me the manifold. It was ready to install except for where the material was added to hold the gasket properly. Although it had been faced off on the gasket face, I had to do a quick hand porting job to remove the material inside the runner. I used a gasket for a pattern and removed everything that would hang out into the passage. I got a carburetor from Harold Droste that was designed for a road-race Cobra. Since I was using a C6 in the Cougar, the divider was just the ticket. I agree with Joe, if you're running an automatic.

KS