Strom 48 carb --what year

[Tim Ayers]

Originally Posted by 36tbird

I never heard before about the "gashawg" reputation of the 48. I thought that the mpg of my 8BA in a '36 pickup with a 48 mounted in the center of a 3x2 manifold sucked because I had not put the vacuum on my Bubba dizzy yet. So, I am now going through the mods recommended, power valve and longer rod, to see how that helps. (I already had installed 97 mj's.) Will report back later.

Not to hi-jack this thread but it got me thinking. I heard the hot set up for a 2x2 for performance and mpg was using 2 81's. Accordingly, I have that set up ready for my upcoming 59A courtesy of Uncle Max. But, just as a 48 can be set up with 97 jets, rod and pv's, could a couple of 97's be set up like 81's for a 2x2 set up? I have plenty of 97 cores, but 81's being higher than a cat's back, maybe they would work in lieu of the smallest Strombergs. Anyone done this?

There is a diff. in the base. 48's & 97's have a 1" and the 81's have a 7/8" I think.

When you see them side by side, it is very noticable. Not sure how much of a difference it would make.

[36tbird]

Tim, I understand the dimension, i.e., cfm, differences. But, it was brought up that some put 97 internals into a 48 to make them more mpg. That to me means you're jetting a 48 down to 97 specs but you would have more cfm due to the larger size of the 48 base. Same would apply, I think, if you took two 97's and jetted them down to 81 specs in order to run on a 2x2 set up. What I am trying to do is save $ as you can find 97's but rebuild-able 81's are pretty rare due to the abuse from midgets and boat racing.

[Tim Ayers]

Originally Posted by 36tbird

Tim, I understand the dimension, i.e., cfm, differences. But, it was brought up that some put 97 internals into a 48 to make them more mpg. That to me means you're jetting a 48 down to 97 specs but you would have more cfm due to the larger size of the 48 base. Same would apply, I think, if you took two 97's and jetted them down to 81 specs in order to run on a 2x2 set up. What I am trying to do is save $ as you can find 97's but rebuild-able 81's are pretty rare due to the abuse from midgets and boat racing.

Reason I mention it is because I think that the smaller base would be part of the needed equation. If you jet a 97 down to 81 specs, you'll have a leaner fuel mixture going through a hole larger than was intended.

I'd assume that the smaller venturi size of a true 81 helps to overcome the lesser amount of fuel 81 carb pass through. I hope what I'm trying to say makes sense.

There has to be a reason Ford spec'd a different base. We all know how frugal Henry was.

[36tbird]

I agree, but again I am talking about a 2 by 2 set up. I'm trying to get the frugality with the hot rod looks of two carbs.

[Tim Ayers]

Originally Posted by 36tbird

I agree, but again I am talking about a 2 by 2 set up. I'm trying to get the frugality with the hot rod looks of two carbs.

I'd suggest getting in touch w/ Uncle Max. He's done countless multi-carb set-ups and has the formula down to a pretty close science.

I'm sure he could give you some specs. that will allow you to use 97's but not break the bank at the gas pump.

That being said, countless others have run 2X2's intakes/carbs and I'm sure someone can shed some light on your question.

[ken ct]

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Ive done this at a few customers request a couple of tmes and all feed back was positive?? . If you measure with a dial caliper the venturie holes in a 48 and a 97 they both measure the same.Yes there is a diff between 97 + 81"s omo ken ct.

[Pete]

Originally Posted by ken ct

Ive done this at a few customers request a couple of tmes and all feed back was positive?? . If you measure with a dial caliper the venturie holes in a 48 and a 97 they both measure the same.Yes there is a diff between 97 + 81"s omo ken ct.

What kind of DIAL caliper do you have that will reach the apex of the venturi??
97= 31/32 plus or minus .003
48= 1 1/32 plus or minus .003

[ken ct]

Im measuring at the bottom? ken ct. All i know it works according to the customers and there happy,so why argue the point. ken ct.

[Pete]

Originally Posted by ken ct

Im measuring at the bottom? ken ct. All i know it works according to the customers and there happy,so why argue the point. ken ct.

I'm not arguing. I was just wondering where they are the same.
You need to measure even with the bottom of the booster and no standard dial caliper will reach in there.

[David J]

Left is 81 & right is 48 . The base of the 81 is marked EE 7/8 and the base of the 48 is marked EE 1 .

Originally Posted by Tim Ayers

There is a diff. in the base. 48's & 97's have a 1" and the 81's have a 7/8" I think.

When you see them side by side, it is very noticable. Not sure how much of a difference it would make.

[36tbird]

What size are the stock main jets and power valves for 81's? I may order some and put them in a couple of 97's for a 2x2 set up.

Another question, does anyone have a lead on a special screw driver to use on power valves? I changed out the one in my '36 yesterday and it was tough to see down into the carb to get the straight slot firmly on the valve. I think it needs some sort of slot screw driver that has a tube around it that will fit down around the top of the p.v. to keep the slot centered as you screw or unscrew it.

[Tim Ayers]

Originally Posted by 36tbird

What size are the stock main jets and power valves for 81's? I may order some and put them in a couple of 97's for a 2x2 set up.

Another question, does anyone have a lead on a special screw driver to use on power valves? I changed out the one in my '36 yesterday and it was tough to see down into the carb to get the straight slot firmly on the valve. I think it needs some sort of slot screw driver that has a tube around it that will fit down around the top of the p.v. to keep the slot centered as you screw or unscrew it.

It's easy to make your own. Get a high quality larger straight blade screw driver and use a Dremel to make a notch in the center. Done.

[Bruce Lancaster]

OK...found my model 40 bowl, 19401 casting number. I don't have the lid...
Secondary Venturi is indeed a slightly heavier casting then the 48; the big difference is around the idle jet area.
Referring to David's pics in post 13, 40 is on the RIGHT, 48 0n LEFT. The diagonal slot connecting the idle jet and its air bleed on 81-97-48 is lacking, surface there is flat. Mine differs slightly from his...on his the air hole is about the same location as the other carbs, whereas on mine the hole is DIRECTLY above the passage down that fees the gas to the base.
I cannot really tell from the pic but assume the lid is slotted above that area.

[David J]

The left right thing in my pic is as I called it . What's wrong is the lid with the 40 is for a 97 . After looking these & others over carefully it's obvious to me there are sub-variations not mentioned yet in this thread . I have 40 & 48 bodys with & WITHOUT part #'s . Also have 40's with the 48 pt # on the body ??? I will post pics when I can make sense of this mess .

Originally Posted by Bruce Lancaster

OK...found my model 40 bowl, 19401 casting number. I don't have the lid...
Secondary Venturi is indeed a slightly heavier casting then the 48; the big difference is around the idle jet area.
Referring to David's pics in post 13, 40 is on the RIGHT, 48 0n LEFT. The diagonal slot connecting the idle jet and its air bleed on 81-97-48 is lacking, surface there is flat. Mine differs slightly from his...on his the air hole is about the same location as the other carbs, whereas on mine the hole is DIRECTLY above the passage down that fees the gas to the base.
I cannot really tell from the pic but assume the lid is slotted above that area.

[Bruce Lancaster]

No more data from me! That body is the only 40 fragment I own!
Look at all the changes in the inlet called out in the bulletins, presumably to control the Stromberg sensitivity to pump pressure. Betcha they were messing with everything else too, trying to get better mileage in idle and off idle since the carb reached venturi flow fairly late in the curve.

[Walt Dupont--Me.]

One more little thing about this Strom carb that we'er going to call a 48 for 1934. On the right side of the bowl it says (Stromberg carb South Bend USA) also casting no. P-19401 on the bowl. On the four 97 I have on my 40 it says (Stromgerg carb ELMIRA N.Y). They must have been made in more than one place. Walt

[Tim Ayers]

Originally Posted by Walt Dupont--Me.

One more little thing about this Strom carb that we'er going to call a 48 for 1934. On the right side of the bowl it says (Stromberg carb South Bend USA) also casting no. P-19401 on the bowl. On the four 97 I have on my 40 it says (Stromgerg carb ELMIRA N.Y). They must have been made in more than one place. Walt

Walt:

I believe the Elmira, NY were where later replacement carbs were made after Stromberg was sold.

Uncle Max, Ken CT., Charlie in NY or others can debunk or confirm this.

Most replacement 97's that come from Elmira, NY that I have seen have a cast embossed circle on the bowl, but do not have a cast 97. Just a blank circle.

Also, I believe they released those triangular-based 97's that have the vaccuum port (like a Holley 94) from Elmira, NY as well.

Kind of strange.

[Barn Junk]

Originally Posted by Bruce Lancaster

No more data from me! That body is the only 40 fragment I own!
Look at all the changes in the inlet called out in the bulletins, presumably to control the Stromberg sensitivity to pump pressure. Betcha they were messing with everything else too, trying to get better mileage in idle and off idle since the carb reached venturi flow fairly late in the curve.

Another thing I have noticed about the very early bowls (P-19401) is that the metal around the inlet fitting was thinner than later versions and they often got broken when removing or tightening the inlet connection.

[ken ct]

Yes most of the arrow head ones are later and have in most a brass booster jet in the venturie base 1 in each barrel. I have a pair of them set up for a 2x2 deal. Anybody want to buy them. ken ct

[Barn Junk]

Originally Posted by ken ct

Yes most of the arrow head ones are later and have in most a brass booster jet in the venturie base 1 in each barrel. I have a pair of them set up for a 2x2 deal. Anybody want to buy them. ken ct

Ken, For a carb guy, you use some strange terminology. No booster, no jet (other than idle jets) or no venturi in the 97 base. The later 97s did have additional brass vent tubes installed in each throttle base bore above the throttle plates to probably aid in the emulsion of the idle mixture. Off idle they would do nothing except restrict total carburetor flow very slightly. The venturi and venturi boosters are in the main body and are the same in all 97s.