dual quad intake

[carlalique]

Need some info/advice; especially from someone who has installed a 409/425 HP aluminum dual quad intake on a 348 engine/791 small port heads. My manifold is an original 64' large port with the Winters snowflake. I was told to install set screws into the head to block off the extra bolt holes. I ported the head as much as possible. I have a .460 lift cam, 9.5:1 pistons. Plan to use Edelbrock 500 cfm with progrssive linkage; mild perfrmance rat rod.
I had this intake and decided to try it rather than lay out another $300 for an Offenhauser dual quad from Summit or big bucks for a 3x2. I want the 2x4 look!
Would the Offenhauser still require blocking the head bolt holes? Would the Offenhauser be a better match to my 348 small port heads; what gasket does the Offy use? Is the Offenhauser a lower rise manifold that might have better low end response than the high rise 64; assume the long runners will be a dog?
Should I proceed with the 64 intake as planned or should I go to the Offy and try to sell the 64 intake? Condition is excellent...what is it worth?

 

[Fathead Racing]

The offy intake is a good medium performance intake that will be a pefect match for your low perfomance heads. The Offy intake will use the lopo intake gaskets that will line up in the stock position. The Offy is made for the lopo heads. The Offy design , I have heard is a better flowing intake than the Winters dual four. When you place a high performance Winters intake on low perfomance heads you will have some metal hanging in the port on the head side, this may impede performance a bit. Your Offy intake will bolt right up with no modifications to the lopo head. Your Winters dual quad intake is worth $200.00 + dollars. Go for it!

 

[Nuts]

2 X 4 Intake

I have installed the stock 2X4 intake on my 409 with 817 heads. The installation was no problem but the car is running rich. I have the smallest jets and the metering rods are adjusted for the rich condition. She runs good at idle put goes very rich when the second carb starts coming in.

Some have said the 600 Edelbrok's will react to changes in jets and rods better than the 500's, but I've not try them. I'm thinking of either going to the aluminum heads or changing over to the Offy intake.

No real knowledge about which way you should go, just my experience.

 

[Tom Kochtanek]

791 heads

I don't know the early 348 heads all that well, aren't those the ones used for the 1958s with the earlier cooling passages? Will that affect anything in his build?

My 2 cents would be to sell the GM intake to someone who needs it for $200-$250 and then buy an Offy on Ebay for about the same price (if you're timely!).

regards,
TomK

 

[models916]

The match game

i used a Hi-po single intake and Holley 750 on my 333 heads to my utter displeasure. So out of tuning control that I replaced it within a week. Offenhauser 2x4 with Edelbrock 600's and all is fine.

 

[T-REXblown409]

So I should use Edelbrock 600's on my 2x4 small port intake with my modified 1147 heads and Isky .488lift Hydr 10:1 CP pistons, 6.135 rods, 454 4"stroke crankshaft, modified valve covers, (What distributor do you suggest I use)?, o and will the 409/425hp exhaust factory headers fit my 1147 heads

 

[Mr. Chev]

The 1147 heads should be ok with that exhaust manifolds. They do come with the 2 1/2 manifolds originally. At least the 350 hp engines did.

 

[Don Jacks]

Start with a vacuum advance equipped dist.and tune from there.Pertronix 2 or3 would be a good choice.

 

[425/409ER]

The factory 409 dual quad intake will be a better choice IMO over an Offy dual quad, why you say? Well the factory 881 is a true dual plane intake, the Offy on the other hand is more like a single plane intake with a divider in the middle of the plenum. The 881 will work good for you.

 

[Don Jacks]

The factory 409 dual quad intake will be a better choice IMO over an Offy dual quad, why you say? Well the factory 881 is a true dual plane intake, the Offy on the other hand is more like a single plane intake with a divider in the middle of the plenum. The 881 will work good for you.

Not with 1147 heads.

 

[32witha409]

I don't think anyone makes a 2x4 manifold for the W's except for Edelbrock. I didn't find anything when I looked around. I could very easily be wrong.

 

[1964SuperStocker]

I don't think anyone makes a 2x4 manifold for the W's except for Edelbrock. I didn't find anything when I looked around. I could very easily be wrong.

Heads up. Edelbrock hasn't made a dual quad small port for several years. If you can find a used one now you had better grab it. I have one that I ran on my 348 for three years. LOVE IT! Its now slated for my 348 in the 59 Elcamino. Only small port made today is the Edelbrock SINGLE four barrel intake. I called them years ago and asked if they would run a batch of small port dual quads and even promised to buy 50 of them. They said NO. The whole reason I called Edelbrock (and everyone else who makes intakes currently) about making small ports because there are so few selections. Now I'm 3D printing them.

 

[La Hot Rods]

Maybe you should buy some bigger heads

 

[32witha409]

Saving my OG 690's for another 409 based build. Just saying.

 

[32witha409]

Heads up. Edelbrock hasn't made a dual quad small port for several years. If you can find a used one now you had better grab it. I have one that I ran on my 348 for three years. LOVE IT! Its now slated for my 348 in the 59 Elcamino. Only small port made today is the Edelbrock SINGLE four barrel intake. I called them years ago and asked if they would run a batch of small port dual quads and even promised to buy 50 of them. They said NO. The whole reason I called Edelbrock (and everyone else who makes intakes currently) about making small ports because there are so few selections. Now I'm 3D printing them.

You 3d print than cast after burning out the printed master?

 

[1964SuperStocker]

You 3d print than cast after burning out the printed master?

No, bolt on single plane that weighs about 6 lbs, just standard 3D printed. We have an extra Extra large format 3D printer with a few special mods. Just finishing the "back fire" blow stuff up phase to determine how large of a Pop-off plate we should run. Then its on to the "my engine got to hot" phase to see if we can melt one on the engine. If I'm going to sell these things then I want just about every possible issue to be weeded out before we go full production. Our production pieces will be Carbon Fiber Nylon. Good to 380 degrees but we have another option of Carbon Fiber that will take it above 500 degrees. 500plus degrees is probably way over kill for no reason though. Working on that now. A new thread on this is coming up very soon.

 

[J.Witt]

I owned a 1961 409/409 bubble top 4 speed SS in the late 60s. Didn't that engine have a dual quad intake manifold on it with Carter carbs? I was certain that mine did but the nay sayers say it didn't. It was a dark grey exterior and a red interior with a plaque on the console that said it was special made for a Lyle Lewter (RIP) in Lubbock, Texas in a Detroit, Michigan GM facility. It definitely was one of the 410ish built in 1961. I tried finding it for several years in the early 2000s but was told by a trusted source that it was totaled and salvaged a couple of years after I sold it in 1970. Think I sold it for a couple of grand.. DUHHH !

 

[Barry Taylor]

Any kin to a John Witt that worked for Friendly Chevrolet in Dallas in the early 60s!

 

[63 dream'n]

A 409/409 was a dual quad engine………!

 

[rstreet]

A 409/409 was a dual quad engine………!

But I believe his car was a 61 so should or could not be a 409 HP as my 61 SS was single carb rated at 360 if I recall correctly
Robert