red_duster74
Well-Known Member
hey im looking at rebuilding my slant 6 but i need some help in knowing what i need because i plan on putting a 4BBL carb on it.. any suggestions?
rebuilding a slant 6
- Thread starter red_duster74
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Charrlie_S
Well-Known Member
What kind of car, and what type of use? Daily driver (around town, or mostly interstate), street/strip, strip only? Fuel milage a concern, etc? Need more info.
red_duster74
Well-Known Member
daily driver and its a 1974 duster with the slant 6 225ci. fuel mileage is a concern but with an old car like this its less important than the beauty of the car and sound of the engine/power
6pakattack
Well-Known Member
The last Dart 225 I built I bored .060 over, 9 to 1 pistons,head shaved 0 .090,1.70/1.44 valves,460/276 cam,Offy intake w/ 390 Holley,Hooker headers,MP elect dist,MSD Ign,TCI 3200 conv,TCI reverse manual VB,8.75 rear w/ 3.90 gears !!At 70 mph I still got 15 mpg on the highway !!:cheers::cheers: Got my next /6 project sitting as I gather parts for another build !!:toothy10:
red_duster74
Well-Known Member
wow and i was told to bore it to.030 over
red_duster74
Well-Known Member
and how many barrels is the carb you put?
1wild&crazyguy
Banned
I did mine .030 over silv o lites, .020 off the block, .080 off the head w/ 1.70/1.44, iron 2 brl intake with holley 350 2brl , mp.460 lift w/268*dur cam, cross drilled std crank w/2.76 gears it got about 23mpg and around 20 mpg w/3.55
red_duster74
Well-Known Member
do you know about how much horsepower you got out of that setup?
nqkjw
Well-Known Member
Something I built a looong time ago.
Bored 0.156" to give 247cid
Cam 311adv dur,104deg overlap,0.495" valve lift
Head shaved down 0.125",big porting,318 valves
Headers
Triple 45DCOE 2 barrel sidedraft weber carbs.
Few other minor bits'n'pieces.
We won't talk about mpg though.:shaking:
Bored 0.156" to give 247cid
Cam 311adv dur,104deg overlap,0.495" valve lift
Head shaved down 0.125",big porting,318 valves
Headers
Triple 45DCOE 2 barrel sidedraft weber carbs.
Few other minor bits'n'pieces.
We won't talk about mpg though.:shaking:
Rengo
Well-Known Member
Up the compression and give it plenty of breathing room by milling the head, don't port, a mild cam, a 2bbl is the most efficient carb, but 4bbls are a little more fun.
red_duster74
Well-Known Member
but will a 4bbl actually affect the power and performace of the car?
Something I built a looong time ago.
Bored 0.156" to give 247cid
Cam 311adv dur,104deg overlap,0.495" valve lift
Head shaved down 0.125",big porting,318 valves
Headers
Triple 45DCOE 2 barrel sidedraft weber carbs.
Few other minor bits'n'pieces.
We won't talk about mpg though.:shaking:
Now that's what eye candy is all about! :-D :-D :-D
ElFin
Well-Known Member
A 4-barrel will give you more top-end speed, but a 2-barrel can be better off the line. Also depends on CFM and jetting, etc.
1wild&crazyguy
Banned
venturi size is gonna make the diff, technically a 390 4 brl has smaller barrels all around, smaller venturi=faster air=better mix=more response/power till the engine can whip it up by itself.
so as long as the secondaries aren't opening too soon, the 4brl is gonna have the same or most likely better off the line.
you can tune around this and get both real close in response/performance, but in the end the 4brl has 40cfm more flowing through it.
the build will make the difference, some street performance builds won't eat all a 350 holley can give, it becomes this almost slowing down with more pedal and speeding up as you let out of it......
one thing that will also cause this is not opening the 2brl flange up to the matching bore size of the 2 brl carb....it just drops out and go's slower from lack of speed even at 3k rpm. the intake becomes the cork.
so as long as the secondaries aren't opening too soon, the 4brl is gonna have the same or most likely better off the line.
you can tune around this and get both real close in response/performance, but in the end the 4brl has 40cfm more flowing through it.
the build will make the difference, some street performance builds won't eat all a 350 holley can give, it becomes this almost slowing down with more pedal and speeding up as you let out of it......
one thing that will also cause this is not opening the 2brl flange up to the matching bore size of the 2 brl carb....it just drops out and go's slower from lack of speed even at 3k rpm. the intake becomes the cork.
Rengo
Well-Known Member
Like it was said, 4bbl gives you more of a top end, but 2bbl gives you a little jump and better fuel economy that the four pack, just take your time on finding some gears for the rear end and you can get a decent toy with great fuel economy.
1wild&crazyguy
Banned
red_duster74
Well-Known Member
well thanks im just looking at giving my /6 a little bit more power
6pakattack
Well-Known Member
390 cfm 4 barrel ! Can't say that I ever calculated HP, but run a 9.89 in the 1/8 mi !!
Rengo
Well-Known Member
if you rebuild it, go with K1 rods. they are like 500 bucks but will be worth the money
805moparkid
Slant and AFX Guy
never had to do 1/8 mile calculations but is that about a 19.** 1/4 mile??
6pakattack
Well-Known Member
Couldn't tell you,all I had was the 1/8 in Immokalee Regional Raceway !!:dontknow: But I didn't build it to be the fastest,I built it to be DIFFERENT !!! And the numerous and varied comments made it all worth while !!:cheers::cheers::cheers::cheers::cheers:
805moparkid
Slant and AFX Guy
i know i know as your fellow slanter! i was just thinking that my stocker went 18.30's in the 1/4...
not stock anymore!
nqkjw
Well-Known Member
One of my cars has a stock slant/904 with a 500cfm edelbrock 4bbl and headers.
Goes well and returns good mpg.Abt 21mpg at our 62mph open road limit.Feels like high 17 - low 18sec 1/4.Haven't run it yet though but I've been racing for 35yrs so you get a feel.
Used to have a holley 600vac on it which was abt the same.
Here's an 1/8 to 1/4 conversion chart for you.
So that 9.89 is around a 15.45 quarter in a perfect world which is a pretty stout slant!!!
Goes well and returns good mpg.Abt 21mpg at our 62mph open road limit.Feels like high 17 - low 18sec 1/4.Haven't run it yet though but I've been racing for 35yrs so you get a feel.
Used to have a holley 600vac on it which was abt the same.
Here's an 1/8 to 1/4 conversion chart for you.
So that 9.89 is around a 15.45 quarter in a perfect world which is a pretty stout slant!!!
805moparkid
Slant and AFX Guy
One of my cars has a stock slant/904 with a 500cfm edelbrock 4bbl and headers.
Goes well and returns good mpg.Abt 21mpg at our 62mph open road limit.Feels like high 17 - low 18sec 1/4.Haven't run it yet though but I've been racing for 35yrs so you get a feel.
Used to have a holley 600vac on it which was abt the same.
Here's an 1/8 to 1/4 conversion chart for you.
So that 9.89 is around a 15.45 quarter in a perfect world which is a pretty stout slant!!!
i awlays just thought it doubled haha... thx for the chart!
red_duster74
Well-Known Member
....One of my cars has a stock slant/904 with a 500cfm edelbrock 4bbl and headers.
Goes well and returns good mpg.Abt 21mpg at our 62mph open road limit.Feels like high 17 - low 18sec 1/4.Haven't run it yet though but I've been racing for 35yrs so you get a feel.
Used to have a holley 600vac on it which was abt the same.
Here's an 1/8 to 1/4 conversion chart for you.
So that 9.89 is around a 15.45 quarter in a perfect world which is a pretty stout slant!!!
so you think a holly 600vac would be a good carb for a street slant 6
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