New intake manifold?

[jscott]

Was watching engine masters last night, they were trying different intake manifolds on a 351w.  Got me to wondering.......Not really sure if my engine is what came in my car, it was born a H code but is currently sporting a Ford 4 bbl intake and, via another post I had the following:  With that date code, there's a 99% certainty you have D1AE-GA 67cc closed chamber castings, 2.19/1.71 valves. You have a Crane stud conversion kit to run the adjustable rocker arms and some unknown brand of steel roller rockers.  

The 4* on the corner denotes a 4V head with the larger ports and valves, so this head was installed by Ford on a 4V engine.

I think you have the date code correct of Dec 1970.

I also feel there is a mild cam inside but other then this info I really do not know what is inside the engine.  I did replace the old, tired Holley 750 with a Summit 750 and am very happy with it, gas mileage is pretty good and I guess performance.   So now after the above mentioned show I was wondering if installing a new intake, like the Edelbrock preform rpm or similar would give me more get up and go?

 

[c9zx]

What intake is on it now? D0AE-L or ???? The Edelbrock RPM or RPM air gap are really good intakes from what I've seen and my limited use on a Boss 347. Chuck

 

[jscott]

 

[c9zx]

The D0AE-L intake is not a terrible intake, in fact it is pretty good for a factory part. It works better if the primary bores are opened up to the secondary size and a 1/2-1.0 inch open spacer is used (increased plenum volume at the top end). The Edelbrock RPM air gap would likely make more torque at the bottom and mid-range due to the reduced cross sectional area of the runners. And make more at the top due due a better design. Only one way to find out if it is worth it or not. Chuck

 

[jscott]

Never replace Dan intake before.  Seems simple enough.

 

[Galucha]

Never replace Dan intake before.  Seems simple enough.

It's not too difficult of a job. Edelbrock intakes usually come with gaskets, but they're not great unfortunately. Get some quality fel pro gaskets and be extra careful setting the new intake on so the bolt holes line up without having to reposition it.

 

[Hemikiller]

From various dyno sheets and a recommendation from Scott Main at Cam Research, the RPM is a great intake for the 4V heads. Dan Jones did a bunch of intake testing on a fairly mild 351C. The results show the RPM airgap is worth about 25-30 torque and hp across the rpm range vs an optimized iron intake setup. 

https://www.corral.net/threads/budget-351c-rebuild-and-dyno-test.2092114/

 

[Don C]

The intake manifold on the 351-C Ford engine is critical as far as torque rate and sequence are concerned. Intake leaks, although very slight, will affect engine performance and may result in oil burning. Apply the manifold with care, making sure it is aligned correctly, front to rear and side to side, and adhere to the following instructions in three steps.

For stock iron intakes:

1. Torque all bolts in sequence to 8-10 ft. lbs.

2. Torque all bolts in sequence to 15-20 ft. lbs.

3. Torque all bolts in sequence to specifications:

5/16" bolts should be torqued to 23-25 ft. lbs.

3/8" bolts should be torqued to 28-32 ft. lbs.

For aluminum intakes:

1. Torque all bolts in sequence to 8 ft. lbs.

2. Torque all bolts in sequence to 15 ft. lbs.

3. Torque all bolts in sequence to specifications:

5/16" bolts should be torqued to 18 ft. lbs.

3/8" bolts should be torqued to 25 ft. lbs.

Be advised that the manifold requires retorquing in sequence to full torque after the engine has reached normal operating temperature.

Installing long studs in the four center holes (9, 10, 11, & 12) will assist in getting the manifold aligned correctly. After torquing the rest of the bolts to their initial torque value remove the studs and install the bolts to their initial torque.

 ​

 

[Galucha]

The intake manifold on the 351-C Ford engine is critical as far as torque rate and sequence are concerned. Intake leaks, although very slight, will affect engine performance and may result in oil burning. Apply the manifold with care, making sure it is aligned correctly, front to rear and side to side, and adhere to the following instructions in three steps.

For stock iron intakes:

1. Torque all bolts in sequence to 8-10 ft. lbs.

2. Torque all bolts in sequence to 15-20 ft. lbs.

3. Torque all bolts in sequence to specifications:

5/16" bolts should be torqued to 23-25 ft. lbs.

3/8" bolts should be torqued to 28-32 ft. lbs.

For aluminum intakes:

1. Torque all bolts in sequence to 8 ft. lbs.

2. Torque all bolts in sequence to 15 ft. lbs.

3. Torque all bolts in sequence to specifications:

5/16" bolts should be torqued to 18 ft. lbs.

3/8" bolts should be torqued to 25 ft. lbs.

Be advised that the manifold requires retorquing in sequence to full torque after the engine has reached normal operating temperature.

Installing long studs in the four center holes (9, 10, 11, & 12) will assist in getting the manifold aligned correctly. After torquing the rest of the bolts to their initial torque value remove the studs and install the bolts to their initial torque.

 ​

View attachment 49879

That trick to use studs to help guide it on is no joke, especially for heavier intakes. I recently put a cast iron intake on an FE build and it would have been really difficult to line up without the studs there.

 

[Carolina_Mountain_Mustangs]

For sure use the studs. I have for intake, transmission and water pump. Oh BTW when I cracked the 73 Mach 1 to head to shop last week the water pump started to leak. It is the original. I will find new seal and bearing and rebuild the original.

 

[Q1SVT]

Was watching engine masters last night, they were trying different intake manifolds on a 351w.  Got me to wondering.......Not really sure if my engine is what came in my car, it was born a H code but is currently sporting a Ford 4 bbl intake and, via another post I had the following:  With that date code, there's a 99% certainty you have D1AE-GA 67cc closed chamber castings, 2.19/1.71 valves. You have a Crane stud conversion kit to run the adjustable rocker arms and some unknown brand of steel roller rockers.  

The 4* on the corner denotes a 4V head with the larger ports and valves, so this head was installed by Ford on a 4V engine.

I think you have the date code correct of Dec 1970.

I also feel there is a mild cam inside but other then this info I really do not know what is inside the engine.  I did replace the old, tired Holley 750 with a Summit 750 and am very happy with it, gas mileage is pretty good and I guess performance.   So now after the above mentioned show I was wondering if installing a new intake, like the Edelbrock preform rpm or similar would give me more get up and go?

The intake you have is a very good one... was used on the Torino's & Montego's beccause it made torque.

The issue is modern carbs have different sized carb pad bores.  Your 750 is a square bore w/ 1-11/16" openings @ intake side.   The L intake is actually a spread bore [primary's are smaller than the secondaries & both are smaller than 1-11/16.  Old days you could buy an adapter, but here is one that you can open up a little on the intake side to match the L manifold....   Make a cardboard pattern off of your intake and use a Dremall to open it up.  A fel pro 60058 base gasket [or two of them]  has correct bores and creates an open spacer between bores..

Can have intake bored also... but both changes will out flow/perform Edelbrocks, and other intakes... YES there are those dyno MULE tests... If you read the details THEY use a dyno 850 carb [1-3/4 carb bores !] the two guys knew how that MISMATCH would FK-up air/fuel flow, add an open spacer [air flow is screwed up even more to flow back into a 4 hole intake]...  or they are dumb & dumber ....   good way to sell intakes  ;^)     Yes I have questioned the two directly... they just have chosen not to comment ...   wonder why LOL   [find old 1970-75 car magazines, the L has been written about many times...] 

. 

 

[jpaz]

The Edelbrock Performer is nothing more than a stock aluminum replacement for the factory cast iron one. The Air Gap is a great way for a noticeable hp gain. The Blue Thunder is also a great intake too. I went with the Blue Thunder because it looked more factory than the Air Gap. And the BT is very similar to the aluminum one Ford used on the B351 in 71. I am very happy with the BT! Installed myself with my disabled left arm. Pretty much an instant 25 ish horsepower gain. I’ve even seen guys paint them to match engine and looks very factory. It’s a beautiful intake!

 

[Galucha]

The Edelbrock Performer is nothing more than a stock aluminum replacement for the factory cast iron one. The Air Gap is a great way for a noticeable hp gain. 

I definitely wish I had known that when I bought my performer intake. Basically the only reason you would ever run a performer is if hood clearance was an issue (but at that point why not just use a stock intake?). Here's the dyno graph from that episode of engine masters mentioned above that compares the performer vs performer RPM. 

 

[jscott]

are there limitations on which intake will work with stock ram air setup?

 

[Stanglover]

Reading through, there's a lot of great info, I'm learning too. 

Using a stock L intake, there has always been much discussion as to the use of the valley pan (turkey pan some call it). It's there for a reason especially (I think) if the exhaust heat cross-over has not been adequately blocked off. If your using anything but the original Autolite carb, even the base gasket with the steel insert won't be enough to prevent burning the carb base, let alone fuel vaporizing out of an overly hot carb. Again there has been many posts on this subject if you care to search.

On installing a manifold, My choice has been to use the valley pan and Fel-Pro paper gaskets using Permatex 2 non hardening gasket sealer. For the critical ends, I chose to use "The Right Stuff" instead of the rubber seals that often don't. Back when my motor had to be rebuilt for a second time (don't ask why) they used the rubber seals and sure enough they leaked and I had to pull the intake and do it right. For long guide rods to align the intake, I took a couple of longer 5/16' bolts and cut the heads off, then used a couple of 5/16" bolts to temporarily hold it in place while installing the 3/8" bolts, then follow what Don had listed for tightening. Another good tip is to use a couple of 1/4" eye bolts, diagonally across the carb base, then use a long rod through the eyes and someone to help lower that heavy intake down squarely into place without messing up your lovely 1/4"+ bead of The Right Stuff. Talking of, run that up the heads by about 1/2" each side, back and front of course.

Other than that it is simple enough.

 

[Stanglover]

The Edelbrock Performer is nothing more than a stock aluminum replacement for the factory cast iron one. The Air Gap is a great way for a noticeable hp gain. The Blue Thunder is also a great intake too. I went with the Blue Thunder because it looked more factory than the Air Gap. And the BT is very similar to the aluminum one Ford used on the B351 in 71. I am very happy with the BT! Installed myself with my disabled left arm. Pretty much an instant 25 ish horsepower gain. I’ve even seen guys paint them to match engine and looks very factory. It’s a beautiful intake!

View attachment 49989

 John, On the Bleu Thunder intake, am I right that the carb base plane is not angled back as is the stock 351C intake. I'm sure I read somewhere that the Blue Thunder intake was developed for the Pantera which of course is a rear engine adaption, therefore the motor will not be in the same orientation, requiring the carb angle to be changed. Does that make sense? Curios if it really makes any difference.

 

[Q1SVT]

Reading through, there's a lot of great info, I'm learning too. 

Using a stock L intake, there has always been much discussion as to the use of the valley pan (turkey pan some call it). It's there for a reason especially (I think) if the exhaust heat cross-over has not been adequately blocked off. If your using anything but the original Autolite carb, even the base gasket with the steel insert won't be enough to prevent burning the carb base, let alone fuel vaporizing out of an overly hot carb. Again there has been many posts on this subject if you care to search.

Yes should always block exhaust crossover unless you drive in winter...    That prevents exhaust heating intake/Air...   Turkey Pan keeps Hot Old from hitting bottom of intake and heating the air flowing ...

LOL, I used both Turkey & the thicker style gaskets... as we did many years ago, did have to mill the flanges.  That will screw with the Cleveland experts   lol    pic included  - pink is Pematex on the turkey pan 

Bottomline, in a street car under hood temps are always high, so AL INTAKES, don't actually differ much from iron.

BUT should always run a Phenolic carb spacer to keep carb heatsink down 

I definitely wish I had known that when I bought my performer intake. Basically the only reason you would ever run a performer is if hood clearance was an issue (but at that point why not just use a stock intake?). Here's the dyno graph from that episode of engine masters mentioned above that compares the performer vs performer RPM. 

View attachment 49995

FYI, the performer RPM has same/similar sized intake runners as stock 351C 4V, the performer has/uses the 2V runner cross-section.. same for the Air Gap both designed for Edelbrock Cleveland AL heads   [really just 2V heads...   Their 2V intake was a smaller runner than stock also...  

 

[Stanglover]

Without going to far off track, and as we were talking about a stock "L" manifold, here's a pic of what I did to block off the heat cross-over. Apart from a 1/16" SS insert in the manifold, I also doubled up and added a piece of .020" SS over the opening in the heads. This was inserted into the paper gasket, hole cut larger to suit and held in place with some Permatex 2. Sorry no pic of that. Another earlier quick fix was to tap the holes in the carb base and insert 5/16" plug screws (set screws). 

Again this has been gone over many times.

 

[jpaz]

 John, On the Bleu Thunder intake, am I right that the carb base plane is not angled back as is the stock 351C intake. I'm sure I read somewhere that the Blue Thunder intake was developed for the Pantera which of course is a rear engine adaption, therefore the motor will not be in the same orientation, requiring the carb angle to be changed. Does that make sense? Curios if it really makes any difference.

Never heard of this intake being developed for the Pantera. It is set up for a 351c in cars like Mustangs and others. I do remember measuring the carb base height for fitting it under the hood with the carb I’m using. I can’t remember the exact measurements, but it fits with no problems. I wasn’t really to worried about adding the ram air kit as my car would not have been made that way cause it’s a Q code. I’m pretty sure it would fit though. 
My engine really runs strong with this intake. Very happy with it!