Holley 2300, 5200 or Weber 38 DGES or other?

[Anonymous]

Hello.

Before I start, here are my specs:
'73 Australian Ford Falcon XA, 250 loghead intake with a wheezy 1bbl Stromberg carb (BOV? something)

I'm currently ready to swap my Stromberg out with a more capable carb. Additionally, I'm a newbie to all of this, so this will be a learning experience for me. I'm slowly upgrading my engine, as I learn about each part, and right now, it's the carburetor.

Does anyone have any suggestions for having a stronger carb that will adjust to my engine as I replace parts such as the head to a 2V, cams, etc. etc.? I'm happy to go with rebuilt, as long it's something I can still get parts for with relative ease.

Thanks, in advance.

Makoto

 

[ruckus68]

I have a new weber 38/38 dges with electric choke for sale if you want it please let me know
$250 shipped
thanks
John

 

[Anonymous]

Hi Makoto,

The question of the ages, thats what you ask. You will get many "opinions" on this one. Let me try some statistics on you.

The 250 is an engine, due to it's bottom end design (rod ratio), that will max good HP up to 5000rpm. Most 250 users build the engine with a 5000rpm redline in mind (cam and other choices). The stock US version of the engine was rated at 95HP at 3200rpm in it's 1973 state of tune. I don't know what the emmisions issues were in Az at the time, but I doubt that would make much difference.

Sizing a carb. The 250 engine could draw 231cfm of air at 3200rpm assuming 100% efficiency. In reality, the stock 250 was no more than 75% efficient. So, a carb that could flow 174cfm was all that was needed.

As you build your engine you will want to focus on focus on improving the efficiency of your engine (higher CR, better cam, headers, porting, etc.). So, a carb that can support you end goal would be a good choice now, assumming you can mount it. Max flow needed. It would not be unreasonable to expect an efficiency ratio or 90% for a well built srteet car. AT 5000 rpm and 90% the 250 will need 270cfm. Since there should be some margin the 5200 would not be a good choice for your engine even though it is an excellent carb (tunable, efficient, etc). Here are some numbers for ya.

Holley-Weber 5200 - 270cfm
Weber 32/36 DGV - 320cfm
Weber 38/38 DGE - 370cfm
Holley 2300 / 350 - 350cfm
Holley 2300 / 500 - 500cfm.


The 38/38 or the Holley 2300 (350) would be my recommendations. Personally, I like Webers as the are easier to tune and more reliable (an opinion based on design and personal experience). Some here will recommend the 2300 / 500. Looks like too much to me. Low end drivability is better with the smaller venturi in the smaller carb. But each to there own.

Hope this is useful - Steve.