opinion: 2 bbl vs 4bbl : stock 318

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ClarkDart70

ClarkDart70

Street Machines Limited
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Ok, so I have been running the all stock 318 since buying the car in March with my 2bbl carb that was just rebuilt.
I am in the middle of an engine tear diown and rebuild and my buddy has given me a cast iron 4 bbl mopar intake off of who knows what and a freshly rebuilt eddy 4 barrel 650 cfm with electric choke.

A part of me wants to put the eddy on but my all original set up works so well.

What are the advantages the 4 barrel has over the 2 barrel?
Is it going to be worth the headach of stripping this 4 bbl intake down? Its EGR and is pretty rusty. Also, the thermostat housing is different sized.

If anyone knows what these numbers mean:

417739153

They are on the front of the 4 bbl intake.

Thanks,
Clark
 
That intake and carburetor are not compatible without an adapter plate. I would say use what you have if you liked it and it worked well.
 
All depends on what you want . The 4 bbl and intake will not help much with stock manifolds and exhaust , not really worth the effort . Especially if you're happy with how it's working now .
 
When my Barracuda was going through its evolution I put a performer and a Holley 600 VS on an otherwise stock 318 with the original 273 single exhaust system. The car picked up a lot.
 
when I got my Valiant I have a stock 318 with a 4 barrel. you don't really notice it until floored, but I port and pollished the stock heads and manifolds since I'm on a TIGHT budget
 
If it were me, I'd use the 2bbl to get it back on the road. Then I'd put the Eddy carb on a regular Performer intake down the road. Since you have the engine out now, what are your cam plans? Exhaust?

I would put a fairly mild cam in it (XE 256, or 262), save up for 2 1/4" dual exhaust (off the manifolds is fine) and then when that is done, put the 4 bbl on. Unless you are planning transmission and rear end work that's as far as I'd go. Much more cam and you'll need a different converter. Much more cam and you'll want more gear, and the 7 1/4" diff will get pretty fragile. Not to mention the need for more compression, bigger heads, etc.

A basically stock 318 with a mild cam, 4 bbl and basic dual exhaust will provide quite a bit more performance than the stock setup, get good gas mileage, and be reasonably resistant to hurting itself. If you're gonna drive the car, do this. If you're gonna race it, well...
 
Any pics of the intake your buddy gave you?

If you're looking for a little extra power, go ahead with the 4 bbl upgrade. As mentioned above, I would also go with a Performer instead of the intake you're talking about. If you don't plan on switching the cam to something better than stock, I would stick with the 2 bbl carb. I'm just not sure how much more power can be gained with just the intake and carb swap. Perhaps somebody else can chime in on this and give a better answer.

I upgraded the 318 in my old Duster. Here's what I did:

Performer intake
600 Edlebrock
Comp Cam w/ springs. I can't remember the lift and duration.
Headers and dual exhaust

I noticed a nice power gain compared to stock, especially when those extra 2 barrels kicked in.

Sometimes it's better to leave things alone if they are working fine. I find whenever I mess with something that doesn't need fixing, I create a lot of unforeseen problems down the road.
 
sr71mopar said:
When my Barracuda was going through its evolution I put a performer and a Holley 600 VS on an otherwise stock 318 with the original 273 single exhaust system. The car picked up a lot.
Click to expand...

I did the same for about 2 days on my Dart. I threw a cast iron intake and carter 4 bbl on and it picked up quite a bit! I was surprised.

Never did find the issue with the afb carb,so I took it off.
 
I agree that a correctly set up 4 bbl will add power to the back wheels on a stock engine. My problem has always been I like to hear the secondaries kick in and there went my gas mileage.
 
That 600 four barrel carb that flows more air than the the 2 brl actually has smaller venturi's....so you get better fuel mixture/metering with 4 corners of boosters.

holley 350 2brl vs 600... theoretically the 2brl allows 175 cfm per barrel...while the 4 brl only allows 150 cfm per barrel...so during cruise when you are only using the primary's...you are getting the effect of an even smaller carb than the 350 2brl.


so keep your foot out of the secondaries and the 4 brl will get better milage...and power.
 
When I first got my dart it was a bone stock 318 with a 2 bbl, 30K miles ran like a champ.

I put on an LD4B and a Holley Street Avenger 670. The difference in power was immediately noticeable and enjoyed thoroughly. The car was still not "fast", but the power difference was substantial. My car even still had most of the stock 2" exhaust piping.

I would not use that cast intake though. There are way too many cheap Performer, etc intakes out there to merit using a cast iron piece.

My .02

Steve
 
thanks everyone! I think I am going to run what stock and make the decision down the road.
I am staying with the stock cam. The car is 63K original miles so I basically pulled everything apart inpsected it and reassembled with new seals. Trying to keep the mods bolt on so they can later be bolted off.

Thanks again!

Clark
 
1wild&crazyguy said:
That 600 four barrel carb that flows more air than the the 2 brl actually has smaller venturi's....so you get better fuel mixture/metering with 4 corners of boosters.

holley 350 2brl vs 600... theoretically the 2brl allows 175 cfm per barrel...while the 4 brl only allows 150 cfm per barrel...so during cruise when you are only using the primary's...you are getting the effect of an even smaller carb than the 350 2brl.


so keep your foot out of the secondaries and the 4 brl will get better milage...and power.
Click to expand...

It sounds logical , but if it were true why wouldn't manufacturers put 4bbls on all their cars for better mpg ? Don't think epa tested WOT so they could have gotten better fleet ratings .
Or would the cost of the 4bbl set up be greater than the money saved getting better fleet mpg ?
 
jerry6 said:
It sounds logical , but if it were true why wouldn't manufacturers put 4bbls on all their cars for better mpg ? Don't think epa tested WOT so they could have gotten better fleet ratings .
Or would the cost of the 4bbl set up be greater than the money saved getting better fleet mpg ?
Click to expand...

emissions/and maybe cost, not everything was performance aimed.

they started back in the late 50's with the whole cleaner emissions deal + with the intro of fuel injection...you can ask the same...why didnt they put FI on everything?

it usually boils down to cost, like why did they **** can adjustable rockers?
or steel cranks, or floating pins...
 
i put dual exhaust, small cam and a cast iron 4bbl intake with a 600 eddy on my otherwise stock 318 and it woke it up alot. if i was rebuilding one and considering the 4bbl i would def put a little more cam since the engine will be apart anyway.
 
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