472/500 Intake MIA

[Mootsman]

Hello everyone

I am new to the forum here...been surfing a couple of weeks and I have really learned alot in a short time...some great experience and knowledge here.

Recently, I have inherited a 1979 Sedan Deville from my Grandpa...very cool car--canary yellow with a white top and white leather interior...decent shape overall, but no show winner.

I am currently rebuilding and modifying the stock Q-Jet for better performance...and I am looking to acquire a stock intake manifold off a 472/500..sounds like a good upgrade to my 425. I'm having no luck rounding one up locally and don't see any for sale on ebay or a few other sites. What's the best way to put your hands on one of these pieces? Any ideas will be appreciated!!!

and, I look forward to learning more about these curious u-boats with wheels...

I'll post some pics of "Weezy" once I get her all polished up.

[Allante North *]

Hello & Welcome Mootsman!

I see your in Memphis and I am in East Tennessee. If you ever get this way I think I can hook you up with a 500 intake. Just PM me or email me and we might work something out.

Don

[Mark --]

I'm in Tennssee as well - 60 miles S/W of Nashville.

I got a 500 intake as well

Mark --

[TorqueInc]

If you can find a 1/2 inch spacer it will help as will the intake modification that I have spoken of here a few times

I think someone has pictures posted here

[Mootsman]

Hey everyone

Thanks for all the offers and suggestions...I found one locally (finally!!!) and I am in the process of removing the center section...Hope to finish tonight or tomorrow night...

I appreciate all the help!!!

Shawn

[stupeds]

can you post pics when you are done? what are you going to use to remove the material? i wanna do this mod myself but dont know how to go about it

[Mootsman]

Stupeds


In answer to your question, I will try to give you a description of how I did the mod. I'll try and figure out how to post pics in the next day or so..I took photos before, during and after.

First of all, I don't have a machine shop...I've been working on cars for 20 years, but I was a little hesitant about this mod...it seemed like a job for the milling machine...well, let me reassure you, you can get the job done with some basic air tools and a little patience...here's what I used:

Dewalt cordless drill---to hog out some of the thicker areas in the center divider...don't drill too deep, though
Reciprocating saw---to make initial cuts at the "web" areas
pneumatic 3" cut off wheel---to cut deeper and a little more precisely
pneumatic die grinder- this tool ended up doing the majority of the work...a word to the wise...you will burn a dremmel up trying to do the work of a die grinder....don't find out the hard way like I did.
1/2" x 1" carbide burr---double cutting w/bull nose--I paid about $10 for this bit at a local abrasives company...

The first thing I did was to scribe straight lines across the front of the primary and secondary bores to give me a line to work to.

Secondly, I went to work removing material by cutting with the saws and drilling to hog out material in the thicker sections.

Thirdly, I used the carbide burr in the die grinder to start shaping up the mess I made. This tool works great...and can be pretty agressive..I removed up to 1/4" of material with this tool...it's easy to get carried away, so be careful!!!
Make sure you get the double cutting burr...it's easier to control

Next, I swapped the carbide burr for a 60 grit stone to help smooth things out a little more....and went over all the area I had just cut with the carbide burr

Finally, I used an 80 grit flapwheel---about 1-1/4" diameter to finish things up...I was truly surprised at the results...looks pretty good to me...and matches closely the pictures I found of this mod on the internet.

I'm sure a milling machine would do this job much quicker....it took me many hours...but I am definitely living proof that you don't have to have any experience with "port work" to do this right...just some destructive tools and a decent compressor!!! and a few bucks for abrasives

Unfortunately...
I haven't been able to bolt the intake on, because my A/C bracket from my '79 Deville doesn't bolt up to this intake. I guess it's back to the junkyards for a '68 A/C bracket unless anyone here knows where I can get one....

Anyway, hope this helps, and I'll try to post pics tomorrow.

Shawn

[davesdeville]

Torque Inc's pics and Tiny Donovan's flow numbers for the modified stock intake manifold are displayed on my site: http://www.www.cadillacowners.com
Look on the left under Deville for Manifold...

[Shoehorn]

The stock manifold weighs a ton, and is a worthless restrictive piece of crap, as is the quardajunk carb. You can get an aluminum edelbrock intake off ebay for abot $250, drop a 800ish cfm edelbrock carb in it and you will be very happy. That engine has already been gimped to hell by tree hugging liberals. Don't put the emissions carb back on.

Check hood clearance before buying anything, unless you don't mind it sticking out.

[BluEyes]

That's a bit extreme when the milled stock intake flows within 5% of the Edelbrock manifold at its worst point.
Plus, the edelbrock manifold removes the AC mount. Sorry Eddy, that makes that manifold a no-go on my Deville.

If you don't want your Quadrajet, send it here, I'll pay shipping. I dunno about the 425/368 motors, but the 472/500's got Q-jets that flowed 800cfm from the factory. If they didn't have the 800cfm unit, then they had the 750cfm one.
Of course, if it is one of the electronically controlled q-jets, you do have to file off the tab that limits the secondary air door to get at the full 750cfm.

[Shoehorn]

I have already thrown the quadrajunk in the trash where it belongs over a year ago. AS far as the flow, you will have to quote some reliable sorce to get me to believe that. Switching to the edelbrock intake is at least a 50 pound savings. Add tuned 180deg runners, and the larger plenum, and there's no way the stock cast manifold can come close.

It's a sad day when a performance upgrade is turned down for air conditioning. You can get a billet Alt/AC bracket setup that doesn't touch the intake, btw. Ebay is a wonderful place.

[davesdeville]

Originally Posted by Shoehorn

The stock manifold weighs a ton, and is a worthless restrictive piece of crap, as is the quardajunk carb. You can get an aluminum edelbrock intake off ebay for abot $250, drop a 800ish cfm edelbrock carb in it and you will be very happy. That engine has already been gimped to hell by tree hugging liberals. Don't put the emissions carb back on.

Check hood clearance before buying anything, unless you don't mind it sticking out.

Ignorance rears its ugly head. Tiny donovan's numbers are reliable enough for me. We've been over the fact that a properly tuned Quadrajet cannot be beat for performance and fuel economy, the only problem is that there's a fraction of a second delay when the air doors open. If the Edelbrock intake is so perfect how come the EGTs are so widely varied between cylinders? Explain to me how in the hell an aluminum intake saves 50 pounds when the stock cast iron one weighs 43? Is the aluminum one buoyant in air? No it's not so shut up and quit spouting off bullshit. Oh, and it's a sad day when a Deville of all cars doesn't have air conditioning.

[Shoehorn]

50 pounds was an estimate. Whoever told your the stock intake outflows the edelbrock is a ****ing moron, and if they didn't give hard data to prove it, you are a ****ing moron for believing it. If said bullshit artist has a dyno sheet before and after, post it. If not, you are stupid. The stock quadrajunk is the best power and economy? God you are retarded. Have you ever seen the bottom side of that piece of shit? I'm guessing no, or you would know why I think you are so stupid. It's an emissions carb you dumbass. It may be the best economy, but there's no way in hell it's going to outperform any major aftermarket carb with the same CFM.

I'm done, I can't argue with this kind of stupidity. I think I'll go build a honda out of all stock honda parts because they are the best and I'll smoke all those ricers with aftermarket crap. Has to be true, some guy said so.

I'll be checking back in to see those dyno results.

[BluEyes]

Since you're too lazy to follow the link that Dave gave earlier to read the data, I'll copy it here...

Lift Stock Milled Edelbrock
.100 64.99 67.90
.200 125.14 126.40
.300 174.40 179.80
.400 190.80 201.90
.500 209.14 215.00
.550 215.60 219.50
.600 223* 227.90

These are both flowed hooked up to a 493 head with a carb on top.
Considering the milled stock intake will only cost you a few gaskets and a weekend of grinding, and you get to keep the AC, I'll stay here.
Besides, you're worried about losing about 20 pounds on a caddy?

Oh, and the Edelbrock intake is not a 180* intake - it is dual plane intake just like the stock one. It IS a high rise intake, but that's all.
Yes, there are companies that make 180* single plane intakes for Caddies. But, on a 5000# street car, do you really want to cut off your lowend torque like that?

As for the q-jets. Yeah, I've been entirely through several different ones. What's wrong about the underside of them? Always seemed fine to me as long as the fuel well plugs aren't leaking.
If you're comparing the Edelbrock or Holley to your original q-jet, it's no wonder you thought the 'jet was bad. Wait 30 years and see how well that other carb performs.
If you rebuild and properly tune a q-jet (I'm not talking stock tuning, either) it is wonderful. Yes, the later emissions carbs need a few more tweaks, but nothing that you can't easily do in an afternoon. I've got three q-jets running on cars I own. Throttle response is right now, as fast as my EFI cars and never a bog, sag, or miss.

Have you read the Cad Company catalog? On a 10:1 500ci motor with the edelbrock intake, headers, ported heads, and a pretty hefty cam the Holley DID make more power. By a whopping 3hp and 6lb-ft.
Q-jet made 477hp, 575lb-ft. Holley made 480hp, 581lb-ft. This is with an 850cfm model 4871, and I'll guarantee you that the q-jet gets better throttle response and mileage.
Around the bottom of page 9 in the Cad Company catalog, they give their take on the carbs, and basically say that for a street car to stick with the q-jet. Now, why would a retailer say to stick with the stock carb when they could sell people Holleys for hundereds apiece?

[notyettoday]

Originally Posted by Shoehorn

I'm done, I can't argue with this kind of stupidity. I think I'll go build a honda out of all stock honda parts because they are the best and I'll smoke all those ricers with aftermarket crap. Has to be true, some guy said so.

sigh, yet another knowitall to try to ruin everything. True, quardrajets get better gas milage, true they flow just as well as an aftermarket carb with a little modification. and ~$30 to rebuild a rochester vs. $300 for an edelbrock+spread to square bore adapter or $250 for an intake which forces you to eliminate ac.. wow.

well enough of that though, i was just curious as to why this modification improves flow and performance? seems to me like they would put the center plenum in for a reason, but i will admit this is an area that i dont know much about