Hot Rods multi-carb and adapters

I really have 2 questions.

First how does one determine what size carb to use on a multi carb manifold? I like fooling
around with old inline 6 ohv and flathead engines. So I really don't know what the flow rate would
be for these engines.
Second question, are 2 barrel to one barrel adapters any good? Thanks John

 

If I was playing with an old tried and true motor I would go with a tried and true setup. Check what he old timers ran and run with it. Remember on most older motors like a flathead V8 or even an inline 6 you are not feeding much motor so you don't need much volume.

On the second question it depends on the adapter a flat plate will allow you go bolt the carb up but an adapter that is slightly raises and tapers toward the plenum will flow better.

Make any sense?

 

I run two, Carter W-1 one barrels on a 250 ci inline six. The W-1's are off 216 ci engines.
You need a smaller engine carburetors or smaller diameter bores in the carburetors in order to keep the air velocity at the correct speed. If the air is to slow ( carburetors to big ) you can have a multitude of running problems from to rich to off idle bogs. Get the carburetors to small, and it will fall down on power at higher rpm. Look for something about 2/3s the size of your engine now for carburetors.

 

Thanks for the replies. The 2 bbl adapter I have I got from JC Whitney back in the late 80's, it is a raised unit that goes from 2 to 1 in a flowing shape. I had wondered about putting it on my Packard 245 flathead 6, to see if any improvement could be had.
John

 

Aftermarket two to one Y adapters for flatheads are reported to be totally useless and only look good.
286merc here on the Hamb actually showed poor dyno performance with these.

 

Question 1 - there is no exact answer, depends on too many variables; however:

http://www.thecarburetorshop.com/Dual1barrelcarbs.htm

Question 2 is much easier - NO (unless you are looking for a paperweight).

Jon.

 

The Packard six of that generation came out in 1937 as a 237 CID with a Chandler Grove (Division of Holley) single barrel carburetor. The carb was nowhere near the quality to which Packard (and Packard owners) was accustomed. Three iterations were tried in 1937, all with poor results. The carb was redesigned for 1938, wasn't much better, and a second iteration was released in 1938. Same results. In mid-1938, Packard gave up completely on the Chandler Grove (Holley) and had Carter release a WA-1 for the remainder of 1938. This WA-1 was retained in 1939. In 1940, the engine displacement was increased to 245 CID; the Carter WA-1 was discontinued, and a Stromberg BXOV-26 was released. In 1941, Carter released a different WA-1 for the 245 CID engine, and the Stromberg was also used; same in 1942. Post-WWII, Packard used the Carter WA-1 exclusively on the 6.

(Opinion) Both the Stromberg BXOV-26 and the Carter WA-1 are excellent carburetors. Hobbyists may find the Stromberg easier to tune to a certain level than the Carter; whereas a professional can tune the Carter to a somewhat higher level due to the metering rod technology.

I won't try to talk you out of the 2->1 adapter and a two-barrel; but if you do, a suggestion:

(1) With a friend you trust and a stop watch, run three zero-60 times, record, average the three, and record the result.
(2) Put the adapter and your choice of two-barrel on the engine.
(3) Again, run 3 zero-60 times, record the results, average, and compare the average to your existing carb's average.
(4) Then, when you have decided to rebuild your original carb, call me for a rebuilding kit.

I am pretty sure of the results, but a gentleman (Dr. von Braun), much wiser than me, once stated that one test is worth 1000 expert opinions.

If you really want a "Hot-Rod-Packard", Zenith offered several type 228AV11 carbs for use on the G.M.C. 270. The 228AV11 will bolt to the Packard intake, and Zenith offered different size venturii as well as an externally adjustable main metering jet for the 228 series carbs. Since the venturii have been not available for several years, you will have to do your homework, and acquire a used carb with the venturi size you want. Not off the shelf, but then if one wants to hot rod, then its possible. A possible donor for a larger venturi would be the G.M.C. 228AV12 which will not fit the Packard intake, but the internal venturi will fit in the 228AV11.

Jon.

 

Hey thanks Carb King, a lot of good info in your reply. I will probably be needing a kit for the '46 Packard.
Thanks John