I think Pete's on the right track - fit the "A" manifold on there with an adapter (you can get one from Speedway or several other vendors) and start hunting for a good (later design) four barrel carb. When the opportunity arises - switch to the later "B" manifold. I like Holley's (390 or 400 cfm 4160) and the Road Demon Jr. (525 cfm) ....but the Edelbrock (500 cfm) has shown itself to work well too.

As Ted spoke of earlier - the four barrels can give you some nice low end torque and mileage that the big two barrels can't - and some top end power too. If you haven't already done so - look at changing to a late distributor arrangement and "quick" advance curve.

 
 Steve Metzger       Tucson, Arizona

You asked about the "big" Holley 2BBL carb vs the "small" Holley teapot carb. What is missing here is that the BIG holley 2BBL flows 353 CFM at the same manifold vacuum that the SMALL teapot flows 400 CFM.

How can this be, you ask? Well because one is rated at 1.5 inches of vacuum and the other at 3.0 inches of vacuum. Hint the 4BBL at 1.5.

So be careful what people tell you and don`t believe everything you read. Pete

The best bet in my opinion is the factory 4 barrel carb and intake off of a '57 312. Had a Carter AFB off a 312 Merc on my '58 292 back in '63-'65. Ran great and very streatable. Your '58 292 should have the ECZ-G heads with the big valves. Makes a good combo.

The a manifold is restrictive so I don't doubt it going to help. Reread Ted's post. I'll stick with my original statement, What you got is better...



Ted's statement:



"From a performance perspective, the two barrel intake with a 500 cfm Holley will outperform the ECZ-A manifold being used with an adapter and later model larger carb. From an efficiency perspective, the ECZ-A manifold with its smaller runners will be exhibit more torque in the lower rpm band while also having the potential for higher mpg under the same driving conditions."



Ted

Lorena, Texas (South of Waco)

"The Master Cylinder"

Enjoying life at the beach in SOCAL

Thanks for the responses! Would there be any advantage when using the Carter WCFB over what I have now? I prefer the

original look, but not if there will be no gain!  JQ

Nope.  Might consider doing that for a future single four intake dyno test but that’s going to be a ways down the road.

Lorena, Texas (South of Waco)

Paul, Of course you are correct. What I meant to say was 1956 and before, but I changed it to read pre-1956. This was all before I had a brainphart and forgot what I was doing. In other words a typical senior moment.



Thanks for correcting me.

"The Master Cylinder"

Enjoying life at the beach in SOCAL

say Ted, have you checked a late 2bbl manifold with 4bbl adaptor against a early small 4bbl manifold with a late adaptor, using the same 4bbl carb?

 lincoln/merc. y-blocks &mel's                                                               bucyrus, ohio.

From a performance perspective, the two barrel intake with a 500 cfm Holley will outperform the ECZ-A manifold being used with an adapter and later model larger carb.  From an efficiency perspective, the ECZ-A manifold with its smaller runners will be exhibit more torque in the lower rpm band while also having the potential for higher mpg under the same driving conditions.

Lorena, Texas (South of Waco)

MC; Shouldn't that be pre 1957?..

Paul