Stromberg BIG 97
- Thread starter Lawrie
- Start date
deuce_roadster
Well-known member
Maybe Lincoln Jim in Wisconsin?
scicala
Well-known member
The 2"hg depression being talked about is how a flow stand is set up to measure total CFM air flow capacity at a manufacturer's facility or other business. 2"hg is the same as 2" of manifold vacuum (mercury = hg).
When flowing a carburetor, after mounting the carburetor on a flow stand, you open the carburetor to wide open throttle (WOT) and adjust the vacuum pump for 2"hg or any other amount you want. When I worked at Zenith Carburetor in Detroit we used 2"hg as the standard. Then when at WOT at 2"hg, the air flow going through the carb was measured (CFM). The higher the depression, the higher the air flow.
Holley measures two barrel carbs at 3"hg depression and four barrel carbs at 1 1/2 or 2" depression. That is why they say a two barrel Holley carb with the same size venturi's and throttle bores flows more air than a four barrel carb (just two of the barrels) with the same size venturi's and throttle bores.
To me this just makes things confusing and comparing apples to oranges sometimes.
Sal
Hey Pete:
Wondering if you could provide more details about valve train work you did?
I'm starting to think two "regular" 97's won't be enough on my 296.
Thanks,
Pete
BANNED
404A cam. Drilled radius lifters. Bronze guides. Titanium 1.7 dia. valves. 4 turn springs with dampers. Titanium retainers.
2 regular 97's will work fine for mild street driving and parades.
Haha. Yeah, I'm no where near that beast you built. 1.6" valves, full porting and relief work.
swanwaco32
Senior Member
I have installed them on a 383 small block chevy after having tripower with Rochester's and they do flow a lot more than the 2g Rochester's..!! Not sure the flathead would take it??
Bored&Stroked
Well-known member
Well that type of driving DOES NOT include me! LOL Hope all is well with you Pete - haven't chatted in awhile, I think we need too.
I have two 48's on my 284 CI engine, is far too little. I'm sticking with this manifold for now (due to the build period, but it is NOT optimal).I'm going to port another "spare" Eddie Meyer top and first try two Holley 2110's (on an engine dyno - want to see if the flow helps), then I'd like to try two Big 97's. Would be a fun experiment.
Take care my ole' friend.
D
tubman
Well-known member
How do you arrive at this conclusion? As far as I have ever known, a small base 2G flows about 275 cfm, while these are rated at 250 cfm.
While these may be alright to use on an SBC manifold, I believe that there may be problems on standard, 3-bolt Ford manifolds. I am very partial to 2G's on a street flathead in a car with a hood. I have found that, while the Mercury manifolds have enough "meat" in them to permit them to be bored all the way down to 2GC size, most Ford manifolds won't take it. I suppose this may not be a problem with "racing" manifolds without provision for exhaust heat, but I would not want to "roll the dice" on a heated Ford manifold. Just one more thing to consider. Unless you bore the manifold to match the throttle bores on the carburetor all the way (and possibly radius the corners like I do), you will not get full benefit of the larger carburetors.
Well that type of driving DOES NOT include me! LOL Hope all is well with you Pete - haven't chatted in awhile, I think we need too.
I'm going to port another "spare" Eddie Meyer top and first try two Holley 2110's (on an engine dyno - want to see if the flow helps), then I'd like to try two Big 97's. Would be a fun experiment.
Take care my ole' friend.
D
Interesting that you are trying this dale. I'm building a blower setup and want to stick with 2x2 on it because three looks too crowded on the Eaton m112. I picked up a really nice 2110 that I need to find a match for. 1 5/32 venturis. Manual choke with plugged valve factory. Havent seen another like it. Basically looks like a big bore replacement for a 94
I wonder if this is a what was called the Bug Spray carb? Bug Sprays were used on VW's when putting a performance 2bbl. set up on the car.
i looked up the number and it wasn't a bugspray carb. pretty sure it was an oem ford unit or replacement from the 50's. the bugspray units have electric choke if I'm not mistaken.
Hmmm. I had what I thought was a Bug Spray on my VW and it had a manual choke. You are probably right. I was a dumb kid when I owed it. Haha.
scicala
Well-known member
I think there were also different venturi sized small base 2 GC's, since they went on a lot of different size engines on GM and marine engines.
So probably the 2GC's from larger engines flowed 275 CFM.
Sal