65-67 Dual Quads

[mygt350]

Did Ford/Shelby offer a dual quad setup on the HiPo 290 using Holley carbs as over counter or as option on the Cobras/GT350's?

[Dan Case]

The simple answer for factory installations with Holley® carburetors is no as far as I know dating back to the 1960s.

The simple answer for over the counter sales with Holley carburetors is yes by "1966".

Cobras could be ordered with a factory installed COBRA 2-4V system with Carter® AFB carburetors starting in mid September 1963.

The over the counter 1966 Ford version with two small Holley carburetors could be purchased and installed on whatever buyers desired. The 1966 kit intake manifold version was followed with redesigned intake by 1967.

[jk66gt350]

The ad in the upper section of the attached picture refers to the over the counter Holley / intake kit that was announced in '66. 

[mygt350]

That looks exactly what I am searching for.

[TA Coupe]

The information or to buy a 2x4 setup?

       Roy

[mygt350]

I am in market for the dual quad Holley 460 version across counter from ford

[JD]

Image rotated...

[6s1640]

MustangteK shows Holley LIST 3360 and 3361 for 1966 2X4V set up.  More pictures on their site.

Good luck

Cory

[shelbydoug]

You can use any 1850, vacuum secondary carbs with progressive linkage. You won't over carb because of the vacuum secondaries.

I would recommend that you don't go crazy looking for rare carbs. Use a pair of 1850, 600cfm Holleys. You will find that the -1 and -2 still have the Ford input lever and are easier to convert the 2x4 linkage to.
They will act like a 600cfm "double-pumper" with an "afterburner" vacuum secondary if your engine can use it. The secondaries don't open unless the engine has demand for them.

Go check out Drew's web page. He may have a couple of 1850's already done that you could use. He just replated a bunch of linkage for the 2xx4's also. You can get a manifold from Carl's Ford Parts.

Be aware that both the original FoMoCo manifold and the Blue Thunder reproduction actually have the port dimensions where they meet the heads closed down a bit.

They really should be gasket matched to get the performance from them you'd expect.

Here's what mine look like.

[mygt350]

Doug, very nice indeed.

[shelbydoug]

The only regrets I have with this set up is that I didn't do it years ago. This thing runs.

[Drew Pojedinec]

When looking for cores
1848s are closest to the original carbs at 485cfm
1849 are 550s
1850 are 600.

My choice is the 1848s for a mild 289. But 1850 cores are cheaper.
As Doug mentioned, too large isn't really a thing.
Worst case, 2, 1850s are really just a 600double pumper.

[shelbydoug]

When looking for cores
1848s are closest to the original carbs at 485cfm
1849 are 550s
1850 are 600.

My choice is the 1848s for a mild 289. But 1850 cores are cheaper.
As Doug mentioned, too large isn't really a thing.
Worst case, 2, 1850s are really just a 600double pumper.

WHY, pray tell, would anyone be putting 2x4's on a "mild" engine? It seems a contradiction of terms to me?

Actually, my choice and preference would be a matched set of BC-BD carbs. My 347 absolutely lights up with them. 1850's are on now and merely my "experiment". An experiment to see if I'll be content with them. They run fine, no problems but there is a noticeable difference in performance. Looks like I already am having doubts.

I am short of one set of BC-BD's right now. I will need to find another set eventually...somewhere?

[Drew Pojedinec]

Me defining mild is something like a 210 or 218@.050 cam.
If your interest is longer drives and efficiency/economy, 2, 1848s or the factory 3x2 actually do as well if not better than many 4v.

[shelbydoug]

Me defining mild is something like a 210 or 218@.050 cam.
If your interest is longer drives and efficiency/economy, 2, 1848s or the factory 3x2 actually do as well if not better than many 4v.

I agree. That is very mild. I'm not even sure a profile like that is available aftermarket? It is probably a custom grind.

That application is likely industrial for something like an irrigation engine used with constant rpm? It likely would have upper rpm limits of something like 4,500 to 5,000 rpm regardless of the induction potential?

Ironically, those applications don't wear the valve train any better then a 237 @ .050 or more.

So really a multiple carb induction with that mild a cam would just be for show. Traditionally multiple carbs are used for more power. The engine needs the capability of pumping "more air", not more glitz with more maintenance, but, to each his own, but I don't see the point.


I DO recall people in the mid '60s with 289 2v Mustangs "scoring" a find of a 4v carb and intake and installing them without any other modifications. Their disappointment was emphasized by the car not going any faster or having more power but with just greater fuel consumption, and advice of "don't make the same mistake" as they did.

Induction improvements are not just a carb change. The entire induction system needs to work as a complimentary package. Multiple carbs systems require more cam, not less.