4bbl
- Thread starter scamp1973
- Start date
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Unless you plan on enlarging exhaust system all the way to the rear bumper, upping compression, swapping stock cam for more lift, and possibly installing oversized valves, in other words building an engine that breaths better, you’re just going to see a drop in fuel economy, and not much performance increase.
A stock slant six can’t pump enough air to take full advantage of a 390 cfm carburetor, and the secondary’s will probably just begin to crack open as rpm’s hit red line.
Headers have no prevision for manifold heat, so when temperatures dip much below 40 degrees, you will suffer drivability issues with carburetor ice, and real bad fuel economy.
Best bet for a stock engine up grade would be to duplicate a proven factory super six setup; a two barrel carb, and a larger exhaust system keeping stock exhaust manifold. It’s simple, a lot less expensive, and most likely you will see a fuel economy improvement as well as better performance.
A stock slant six can’t pump enough air to take full advantage of a 390 cfm carburetor, and the secondary’s will probably just begin to crack open as rpm’s hit red line.
Headers have no prevision for manifold heat, so when temperatures dip much below 40 degrees, you will suffer drivability issues with carburetor ice, and real bad fuel economy.
Best bet for a stock engine up grade would be to duplicate a proven factory super six setup; a two barrel carb, and a larger exhaust system keeping stock exhaust manifold. It’s simple, a lot less expensive, and most likely you will see a fuel economy improvement as well as better performance.
Johnny Dart
Well-Known Member
I ran an Edelbrock 500 on a stock motor with Clifford headers/intake & electronic ignition. 2.25" free flowing exh.
The car ran very good. Are you taking full advantage of the extra fuel/air,no. But you can tune it to run well.
I've run them all. From 1bbl-4bbl.
IMO, skip the 2bbl, because it will be a matter of time untill you want to switch to a 4bbl.
Clifford intakes have a built in provision for water heating/cooling.
It actually works very well. It keeps the intake/carb warm in the winter,and cooler in the summer.
And no,this motor isnt stock.....
The car ran very good. Are you taking full advantage of the extra fuel/air,no. But you can tune it to run well.
I've run them all. From 1bbl-4bbl.
IMO, skip the 2bbl, because it will be a matter of time untill you want to switch to a 4bbl.
Clifford intakes have a built in provision for water heating/cooling.
It actually works very well. It keeps the intake/carb warm in the winter,and cooler in the summer.
And no,this motor isnt stock.....
ir3333
Well-Known Member
Johnny D..that is an awesome looking package you have there..i love it!
Not all Clifford intakes have a hydronic hotspot under the carburetor. I have one of the heatless intakes c. 1993 on my car, and had to fab up a hotspot to be able to drive the car in spring & fall in Maine.
Yes the 500 +cfm carburetors will allow the engine to run, but a smaller carb closer it the needs of the small displacement slant will give better fuel economy and throttle response.
Johnny Dart
Well-Known Member
:thumbrig:
Johnny Dart
Well-Known Member
Fingers
Active Member
Something to keep in mind.
A 600 Holley 4 barrel (1850) and a 350 Holley 2 barrel (7448) have the same size throttle bores.
A 350 works quite well on a 225, therefore, the 600 should too.
If the secondaries are not required, they wont open.
I have a 600 on a Clifford Hyper Pak, with headers, a 2"exhaust, on a stock 225 slant. Not ideal, but drives just fin, and goes way better than stock.
A 600 Holley 4 barrel (1850) and a 350 Holley 2 barrel (7448) have the same size throttle bores.
A 350 works quite well on a 225, therefore, the 600 should too.
If the secondaries are not required, they wont open.
I have a 600 on a Clifford Hyper Pak, with headers, a 2"exhaust, on a stock 225 slant. Not ideal, but drives just fin, and goes way better than stock.
Bone stock little 170/6 driven daily........
I drove this car over 4k with the one barrel and factory exhaust and was getting about 20 miles per gallon.
Know I am getting an easy 24 MPG.. runs cooler on hot days and idles smooth and it likes the 390 Holley and bigger exhaust.
Not one problem arisen by doing this with a bone stock 170/6.
I drove this car over 4k with the one barrel and factory exhaust and was getting about 20 miles per gallon.
Know I am getting an easy 24 MPG.. runs cooler on hot days and idles smooth and it likes the 390 Holley and bigger exhaust.
Not one problem arisen by doing this with a bone stock 170/6.
cheyne68dart
slant-six 225
Do they make a adapter from the one barrel to the two barrel with out having to replace manifold?
bkd
No more Scoops
Nope not that I know of, 2bbl manifold is all
cheyne68dart
slant-six 225
That's a bummer!what if you modified the manifold would that?
BillGrissom
Well-Known Member
I recall seeing 1 bbl to 2 bbl adapters on ebay. They are rare and fairly expensive (~$50). Also, there are quite a few different 2 bbl patterns, so would take a lot of research. A 2 bbl slant intake would seem easier and less risk, if you also get the throttle linkage brackets and kickdown.
cheyne68dart
slant-six 225
Yea that's true. That would prolly be the best and smartest thing to do thanks!
67 gt
A Wog boy who loves his Mopars !
johnny D love that engine bay!! thats 1 cool Dart.I ran an Edelbrock 500 on a stock motor with Clifford headers/intake & electronic ignition. 2.25" free flowing exh.
The car ran very good. Are you taking full advantage of the extra fuel/air,no. But you can tune it to run well.
I've run them all. From 1bbl-4bbl.
IMO, skip the 2bbl, because it will be a matter of time untill you want to switch to a 4bbl.
Clifford intakes have a built in provision for water heating/cooling.
It actually works very well. It keeps the intake/carb warm in the winter,and cooler in the summer.
And no,this motor isnt stock.....
Johnny Dart
Well-Known Member
Thank you.....:glasses7:
Johnny D: Nice engine compartment. Where is the engine (Can't hardly see it as it blends in with the surroundings like a chameleon)...
Johnny Dart
Well-Known Member
Yep :cheers: It don't get much better then this Johnny Dart
my screen saver for motivation :happy2:
my screen saver for motivation :happy2:
Johnny Dart
Well-Known Member
Thank you Mike........:dink:
AHamilton
Well-Known Member
Johnny Dart...That motor looks so clean, doesn't even look like you drive it. =)
I too have run a stock internal 225 with Clifford headers, Intake,390 Holley,split 2 1/2'' pipes from the shorty headers Y'ed into 2 1/2'' single exhaust,Flowmaster 40 muffler and a 2 1/2'' tail pipe. 2.94 rear gears. Later went to a 500 Edelbrock when the 390 started to act up. Edelbrock worked better over all.
This is just my application,,,Your results may vary.....
This is just my application,,,Your results may vary.....
I want to thank everybody for the advise and awsome pictures,sorry i didnt say thank you sooner,but my laptop crapped out,the exhaust on my car has clifford headers,glasspacks and flamethrowers.since i dont have the know how to do an upgrade to the internals on the motor,i just want to do what i can with what i have since its not broken or burning oil.
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