All Small Six Big log manifold what size holes for twin carburetors

[ActionYobbo]

Where can I get steel base plates to weld to the log manifold to do a twin carburetor setup? What size holes do I need to put in the manifold?

I edited the title to better represent what I need to ask

 

[vssman]

Typically, triples are run with an Offenhauser intake that you can get off of Summit Racing or Exeter Auto Supply, Exeter CA (they are the distributor). A few have fabricated their own carb mounts but they were custom.

 

[DON]

Typically, triples are run with an Offenhauser intake that you can get off of Summit Racing or Exeter Auto Supply, Exeter CA (they are the distributor). A few have fabricated their own carb mounts but they were custom.

Question on Small 6. I doubt seriously you could by them. I am assuming that you are talking about cutting the log the log off. Plates would have to be fabricated

 

[vssman]

Question on Small 6. I doubt seriously you could by them. I am assuming that you are talking about cutting the log the log off. Plates would have to be fabricated

No, that’s not what the OP is asking. He wants a triple carb set up. You don’t have to cut the log off. Use an Offy intake or make 2 carb mounts.

 

[ActionYobbo]

To be more clear I intend to machine a flat on the log near to 2 and 5 intake and silver solder on carburetor mounts and run a bridge between them with a 2 barrel EFI carburetor mounted above the stock position but feeding the 2 new locations only and block off the stock (center) hole.
I have seen a few pictures of tripples done with steel plates brazed/soldered on but no mention of where the plates came from. Possibly I could use flathead v8 exhaust header flanges and cut them to fit. The whole setup will put the carburetor 1.75” higher which still leaves some room for a low profile hat

 

[ActionYobbo]

I have not been able to find what I need so I am going to see if I can find someone local who can cut them from 3/8 plate using a gasket as a template

 

[ActionYobbo]

What size holes should I make in the manifold for the 2 carburetor setup. The stock hole is 1.75 but That will be hard to do above ports 2 and 5. Smaller size like 1.5 is the biggest that I could do with out welding to build up the area needed to go bigger. What’s the hive say? 1.5+1.5=3
3-1.75= 1.25 bigger than stock. If I went down to 1.375 it’s would still be a gain of 1 inch

 

[Rmoore45]

Go to https://sendcutsend.com/

If you have access to CAD software you could draw up what you want and have SendCutSend make it for you. They also have quite a few templates already setup that might work for your application

 

[ActionYobbo]

Go to https://sendcutsend.com/

If you have access to CAD software you could draw up what you want and have SendCutSend make it for you. They also have quite a few templates already setup that might work for your application

I am still in the pencil and paper skill level. I just ordered some steel to make what I need and started doing setups.

I think I will use a Webber 38/38 for now and change to efi and turbo later. The earlier hole size was 1.5 so I think that 1.5 should work for this motor.

Edit to add. I used a flow calculator and 2 holes at 1.5 are equal to 1 hole at 4.5