Anyone know what the CFM is of a 1969 318 Stock 2 barrel carb ?
CFM 318 2 Barrel Carb ???
- Thread starter George Jets
- Start date
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I think 280 ...... my memory may have failed me
Copied and pasted from elsewhere here. CFM by the factory wet flow rating.
2-Barrels
273 ~ {1964 thru 1969}
Carter BBD {1.437" Throttle Plates x 1.063" Venturi}.......... 275 CFM Rating
318 ~ {1968 and up}
Carter BBD {1.437" Throttle Plates x 1.186 Venturi}............ 285 CFM Rating
360 ~ {1971}
Holley {1.563" Throttle Plates x 1.343 Venturi}................... 350 CFM Rating
383 ~ {1962 thru 1971}
Carter BBD {1.563" Throttle Plates x 1.313" Venturi}.......... 365 CFM Rating
400 ~ {1972}
Carter BBD {1.563" Throttle Plates x 1.313" Venturi}......... 365 CFM Rating
2-Barrels
273 ~ {1964 thru 1969}
Carter BBD {1.437" Throttle Plates x 1.063" Venturi}.......... 275 CFM Rating
318 ~ {1968 and up}
Carter BBD {1.437" Throttle Plates x 1.186 Venturi}............ 285 CFM Rating
360 ~ {1971}
Holley {1.563" Throttle Plates x 1.343 Venturi}................... 350 CFM Rating
383 ~ {1962 thru 1971}
Carter BBD {1.563" Throttle Plates x 1.313" Venturi}.......... 365 CFM Rating
400 ~ {1972}
Carter BBD {1.563" Throttle Plates x 1.313" Venturi}......... 365 CFM Rating
Last edited:
OK, Perfect Guys
Just what I was looking for.
Thanx
Just what I was looking for.
Thanx
Keep in mind those are at 3"Hg depression. To compare to typical 4bbl divide by 1.41421351 to get the@1.5"Hg depression flow.
Sounds just like the way they count votes, in fraction of votes.
.75 for them and 1.25 vote for the big guy.
Lol! Not quite.....the Holley 2245 I ran on My "Killer6" was rated @385cfm, but at the time I didn't realize that was at 3"Hg, it really only flows 272cfm at 1.5"Hg. Basically half of a 550cfm 4bbl.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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yabut
if your Smoggerteen barely pulls 3" then yur big fat 500 is only what? a 355?, and don't forget, the Carter rating is different from a Holley. One of those is wet, and the other is dry.
And besides all that, the stock smoggerteen probably tops out at under 285cfm max capability anyway.
That's why I keep saying, installing a 4bbl on a stock Smoggerteen is almost a waste of time. Oh sure it will make a lot of noise, but noise ain't power....... unless you're a ricer. With 2.76 gears it will be a looooong wait to get to the actual power that the 4bbl might make; 4400 rpm might be 46mph, yeah by that time 2 blocks have gone by.......
lol
if your Smoggerteen barely pulls 3" then yur big fat 500 is only what? a 355?, and don't forget, the Carter rating is different from a Holley. One of those is wet, and the other is dry.
And besides all that, the stock smoggerteen probably tops out at under 285cfm max capability anyway.
That's why I keep saying, installing a 4bbl on a stock Smoggerteen is almost a waste of time. Oh sure it will make a lot of noise, but noise ain't power....... unless you're a ricer. With 2.76 gears it will be a looooong wait to get to the actual power that the 4bbl might make; 4400 rpm might be 46mph, yeah by that time 2 blocks have gone by.......
lol
A hydraulic roller 318 or a pre 1973 318 responds pretty well to a four barrel though. The 1969 318 in question responds the best of all the eighteens to performance upgrades with the nearly 9.5:1 compression. A great place for one of the Holley 4165 or 4175 ThermoQuad or QuadraJet replacement 650 spread bore carburetors.
72Dart6pack
Harder Better Faster Stronger.
I just bolted a few on to be safe. So your asking the wrong guy. More is always better. 
'91 318 stock
factory intake manifold,
stock camshaft. Stock heads, stock bore.
Stock, stock, stock.
2 to 4 barrel Mr. Gasket adapter.
1406 electric choke carburetor.
Starts great, idles nice, runs great and makes good power.
Like it better than the Stock '76 360 factory 4 bbl. that came out.
Guess that's because of the stock 9.2:1 cr
and the factory closed chamber 302 heads.
The factory TBI 2 bbl intake manifold is a dual plane mid rise design. Good size Plenum on those.
Power to the People
Here it is up and running:
factory intake manifold,
stock camshaft. Stock heads, stock bore.
Stock, stock, stock.
2 to 4 barrel Mr. Gasket adapter.
1406 electric choke carburetor.
Starts great, idles nice, runs great and makes good power.
Like it better than the Stock '76 360 factory 4 bbl. that came out.
Guess that's because of the stock 9.2:1 cr
and the factory closed chamber 302 heads.
The factory TBI 2 bbl intake manifold is a dual plane mid rise design. Good size Plenum on those.
Power to the People
Here it is up and running:
I have NEVER put a 4bbl/intake on a 318 and have it not perform better. Noticeable by the seat of the pants ! Even with single exhaust it was a difference. And I have done it a ton.... just say'n
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
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- 26,225
- Reaction score
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I said on a stock Smoggerteen.
I have done it several times as well; and the answer was always the same; with 2.76s the 4bbl makes a lotta noise, but nothing happens until past 35 mph. Waste of time, waste of money.
Well except for passing, if you put 3.23s in it; then 55 in second is about 3300rpm..... so lemmee guess 6 hp over the 2bbl, which tops out right about there.
Best bang for the buck, no contest, for a Smoggerteen is a 2800TC, and second best is 4.10s or at least 3.91s. If you then put a 4bbl on it (stageIII), you gotta also get rid of the Y-pipe, upsize the exhaust, and install a tach; cuz churaschit your gonna leave it in first gear too long and pump up the lifters.
But for all the cash you spend on stage III, without pressure and a cam, how much power can any 4bbl get you on a 4400 power-peak? I mean at 60% VE, that Smoggerteen is not likely gonna pull more than 250cfm, it don't care if it's a 1-bbl or 8bbls, if it cannot physically pull 250 past the valves, the 250 is all it will pull.
Now, I'm talking 250@1.5, so you know, a stock Smoggerteen with a 4bbl intake plopped onto it, is not likely to pull the intake down that far in any case.
But hey, I hear ya. I used to have a winter engine, a fresh 1973 Smoggerteen with a nice big 850TQ on it, and the TTIs plus dual full length 3" exhaust from my HO367 summer bruizer. And a tach. And some decent valve springs. And it went like a scared rabbit ..................... with a 2800TC and the 4.30s from last summer, lol.
But after the 2.76s go in for the snowy months....... meh. The 2800 helps it get off the line, but if I let the trans shift by itself, the engine may stay at 2800 all the way to ~80 mph. But even if I run it thru the gears, I'll only hit the shift rpm once on the way to 60mph, ending at 3300 in Second, with the 4bbl WOT and howling the TQ-moan ....... but you know; it's only flowing whatever the engine can pull, say ........... 250 cfm?
Oh yes it does sound nasty. But noise ain't fast and especially, not quick.
I have done it several times as well; and the answer was always the same; with 2.76s the 4bbl makes a lotta noise, but nothing happens until past 35 mph. Waste of time, waste of money.
Well except for passing, if you put 3.23s in it; then 55 in second is about 3300rpm..... so lemmee guess 6 hp over the 2bbl, which tops out right about there.
Best bang for the buck, no contest, for a Smoggerteen is a 2800TC, and second best is 4.10s or at least 3.91s. If you then put a 4bbl on it (stageIII), you gotta also get rid of the Y-pipe, upsize the exhaust, and install a tach; cuz churaschit your gonna leave it in first gear too long and pump up the lifters.
But for all the cash you spend on stage III, without pressure and a cam, how much power can any 4bbl get you on a 4400 power-peak? I mean at 60% VE, that Smoggerteen is not likely gonna pull more than 250cfm, it don't care if it's a 1-bbl or 8bbls, if it cannot physically pull 250 past the valves, the 250 is all it will pull.
Now, I'm talking 250@1.5, so you know, a stock Smoggerteen with a 4bbl intake plopped onto it, is not likely to pull the intake down that far in any case.
But hey, I hear ya. I used to have a winter engine, a fresh 1973 Smoggerteen with a nice big 850TQ on it, and the TTIs plus dual full length 3" exhaust from my HO367 summer bruizer. And a tach. And some decent valve springs. And it went like a scared rabbit ..................... with a 2800TC and the 4.30s from last summer, lol.
But after the 2.76s go in for the snowy months....... meh. The 2800 helps it get off the line, but if I let the trans shift by itself, the engine may stay at 2800 all the way to ~80 mph. But even if I run it thru the gears, I'll only hit the shift rpm once on the way to 60mph, ending at 3300 in Second, with the 4bbl WOT and howling the TQ-moan ....... but you know; it's only flowing whatever the engine can pull, say ........... 250 cfm?
Oh yes it does sound nasty. But noise ain't fast and especially, not quick.
Correct. Heck, even the hydraulic roller version will have trouble in a heavy vehicle with tight factory converter and tall tires and tall gears. And the 1984 7.8:1 smogger I had with a crane energizer, Weiand Xcellerator, and 3.21 gears in a '76 Warlock (Bought, Not Built!) had less torque than a good slant six. Hey AJ, your inbox is full. I was going to give you a shout here for a minute. Thanks!
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