Good…. So I guess you can stop telling people that a single 715 is way too big for a 289 eh Doug? 😂😂😂😂
715 is a great size in a Holley due to venturi/throttle bore relationship.
For a driver, I’m more of a fan of the 3x2 setup, but for all out power, it is hard to beat 2x4.
If you want a hybrid, building two 1848s is a worthy venture.
Oh and regarding the float issue, remember the carbs are backwards and probably not level. Most backwards 2x4s run way better with the secondaries a hair lower than normal. (Yes the float level can richen the a/f ratio even at idle)
Yes I do still think a 715 is too big on a 289 in a single 4 on the street. Even on the track I find them flat and lacking crispness. I'm constantly waiting for the power to come on. I feel like I can be checking my email?
If I might quote Ford on that subject here, "a 600cfm carb on your small block Ford is all you need except if you are intending to run at Lemans". That's the horses mouth if you ask me.
Two 600's on a Ford 2x4 intake is not to big at all. It has to do with the throttle opening progression and the throttle crispness that is maintained. I'm not running a 289 though. It's a 347 with AFR heads. A bit of a different animal.
To me, a 4776, 600cfm double pumper is way more responsive then a 715 ever was or ever will be.
Just two 1850's with progressive linkages are similar to a single 4776 response wise but with after burners opened by engine demand and a way better intake manifold then the S2MS Cobra.
In all fairness to Holley though, what has to be considered here is the intake manifold design. All of the Ford 2x4 intakes have better fuel distribution then even the COBRA S2MS intake does.
What is now run in "Vintage" is a Blue Thunder S2MS which has additional runner volume cast in and even those manifolds are internally reworked but don't say anything that is a secret no one is supposed to know?
The two small block 2x4 Holley intakes both have wide open throttle characteristics of an individual runner intakes, particularly the C6OA "Trans AM" intake and it's variants. That affects throttle crispness and fuel distribution. As cast it has nearly identical runner lengths of around 4.5 inches. A number that the Weber intake manifold design people claim is about optimum.
I only have one FE intake, that's my C7ZX "mediumn riser". It could be a lot better but I think the main issue with that one is lack of "line of sight" to the valves and runner lengths being too long?
So while you are talking about optimum throttle venturi ratios of the carburetors, I'm talking about the complete package results.
So what's it to you about which carb is "good" and which is "not so good"? You're gonna' get 'em all to restore anyway. And you should. I can't think of anyone who does better work on Holleys then you. The only problem with your carbs are they are too pretty to get dirty!
Here is what the '66 289 Ford High Rise looks like.