This again.... 4bbl on a 318 with a 2bbl

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Why would a four barrel make a 318 run like crap? Even if otherwise stock?

Heck, Chrysler Corp put four barrel carbs on 273s. And two four barrel carbs on 318 poly motors in 57-58 Plymouth Furies.

500 cfm AVS 2 on an otherwise stock 56 Plymouth 277 poly (factory four barrel motor):

1769537421590.jpeg
 
yeah, don't run a hokey *** 2bbl to 4bbl adapter. might as well keep a 2bbl on there at that point for what the hassle is.

no half steppin'

and disregard any nonsense about port mismatch or it running bad or getting considerably worse mileage. that's all piss poor hot rod folklore and dude's that couldn't tune their way out of a wet paper bag.

KISS: 500~650 carb, performer or factory 4bbl, get a decent curve in a factory distributor, sort out the linkage, cable and kick down and ship it. she'll sing the song you wanna hear. trust.

[next up: george jets recommends a HEI that you don't need-- with pictures!]
 

junkyardhero said:
recommends a HEI that you don't need
Click to expand...

Funnily enough, I did have an HEI on there for a while, but the factory distributor took a crap and I replaced it with a Pertronix billet shiny looking one, getting rid of the HEI in the process.

That distributor came with different springs to tune the curve, but it's left on the default for now.

Last time I looked on marketplace there were some cheap(ish) factory manifolds. I'll take another look on there and see what's close by, I don't mind if it's grubby looking as I'll clean it and paint it before installing it.

Ideally, I'll be selling a 2bbl set up here shortly to offset the 4bbl cost.

Really appreciate all the info so far, like I mentioned, before reading the threads here it was all "port mismatch" and "run like crap"
 
There's a LD4B for sale right now down in the performance for sale thread. $250. Looks like some port matching may have been done, or, opened up for a 340/360. Ask.
 
Mopar built very many 318s in the later years with the 360
size Cast Manifold and a Thermoquad carb.

Do not tell the 318 in my 4000 lb. (Stock Compression/.375 cam) Aspen
Wagon O/SA Stock Eliminator that it will not work well. It runs consistant 11's
and has held several National Records.

In dyno tests and on the track any aftermarket manifold made very little
more and often many made less HP than the stock 080 factory manifold
below 6000 RPM.

My .02 = For Free!

Flame Away!!
 
CRUZE 418 said:
There's a LD4B for sale right now down in the performance for sale thread. $250. Looks like some port matching may have been done, or, opened up for a 340/360. Ask.
Click to expand...

Looks like it has a center thermostat location, not sure if that's going to when with my factory AC.

If it weren't so dang cold I'd go take a look at the brackets and pipe on the current engine to see if I can figure out a center thermostat vs the offset one.
 
GTX JOHN said:
Mopar built very many 318s in the later years with the 360
size Cast Manifold and a Thermoquad carb.

Do not tell the 318 in my 4000 lb. (Stock Compression/.375 cam) Aspen
Wagon O/SA Stock Eliminator that it will not work well. It runs consistant 11's
and has held several National Records.

In dyno tests and on the track any aftermarket manifold made very little
more and often many made less HP than the stock 080 factory manifold
below 6000 RPM.

My .02 = For Free!

Flame Away!!
Click to expand...
I read over the rules for the class your racing in and if I understood it correctly it stated that you have to run factory lift cam, but higher ratio rocker arms are permitted. How can you run stock lift with a higher ratio rocker arms?
 
Last edited:
GTX JOHN said:
Mopar built very many 318s in the later years with the 360
size Cast Manifold and a Thermoquad carb.

Do not tell the 318 in my 4000 lb. (Stock Compression/.375 cam) Aspen
Wagon O/SA Stock Eliminator that it will not work well. It runs consistant 11's
and has held several National Records.

In dyno tests and on the track any aftermarket manifold made very little
more and often many made less HP than the stock 080 factory manifold
below 6000 RPM.

My .02 = For Free!

Flame Away!!
Click to expand...
Sounds like you have a well set up car. Doesn't it take 500-550 horsepower at the flywheel to get a 4,000 pound car into the 11's?
 
Edelbrock 500avs2, performer intake and recurve the distributor. Since you're not racing it the smaller carburetor will give you better throttle response and low end torque which is what you want in a truck.
 
For whatever it's worth here, I've attached a couple of photos. One is of the factory 360 in my '79 Dodge van with A/C and the other is the factory 318 in my '87 Dodge Pickup with A/C.
Looks like they both have the offset thermostat housing to clear the A/C pump.
I'd also like to put a 4 Barrel on my pickup, and possibly an RV cam for towing, though I don't really want to tear into the engine too much as it's only got a little over 40k original miles on it. I used the truck once last year to tow my Barracuda 100 miles to the Mopar Showdown. It definitely lacked power but I may also be using my newly acquired 79 Dodge modified van with the 360 4 barrel as my future tow rig.

20260127_150731.jpg

20240604_182157.jpg

79 Dreamer Van_Pass Side 1-12-26.jpg
 
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Intake recommendation: It's a truck, what it needs is low end torque. Find an Edelbrock Sp2P intake for a 318. Since it is made for a 318 it has the narrow ports that match your heads. You can often find them cheap because most people don't understand what they are for - post a wanted ad here on FABO. Narrow runners maintain flow velocity at lower RPMs. I had one on a truck that I used to haul 14 cords of firewood a year and I swear you could pull stumps with that 318.
 
abcdefghii said:
Really appreciate all the info so far, like I mentioned, before reading the threads here it was all "port mismatch" and "run like crap"
Click to expand...
Lots of reasons to get the "run like crap" response when doing this conversion. I've seen a bunch of them:
-Didn't COMPLETELY eliminate the Lean Burn system.
-Still trying to run the locked-in late LB or the dual-pickup early LB distributor
-Didn't wire in the new ignition properly
-Trying to run a cheap-azz $50 Amazon all-in-one distributor
-Distributor advance hooked to incorrect vacuum source
Notice that none of these has anything to do with the carburetor itself or the fact that it's now a four barrel...
 
318willrun said:
4bbl will help the power on your truck, both part throttle and full throttle. I like 600 cfm's, dual plane intake that supports your accessories. You can use your current 2bbl linkage, with a small amount of creativity. I've done it a bunch.
Click to expand...
Same here. Edelbrocks, cast iron early 340,Thermoquad spread bore late 340 and 360.
Do you have A/C ? you may need one with the off set thermostat housing.
 
Edelbrock Performer intake and either an Edelbrock 600, or a Holley 600 vac sec carb, is the best all round 4BBL package for a 273 / 318 in my opinion. Both items are relatively cheap and available. Remember that you'll need a decent twin system exhaust to take advantage of the 4BBL setup, headers are great but not necessary. Best of luck!
 
Dan the man said:
I read over the rules for the class your racing in and if I understood it correctly it stated that you have to run factory lift cam, but higher ratio rocker arms are permitted. How can you run stock lift with a higher ratio rocker arms?
Click to expand...
NO SIR............Wrong!

YOU MUST run 1.5 rockers and not a thousand more (They may be UNDER
but not OVER!

The pistons must be Flat tops without any Valve notches unlike the earlier 318 pistons
that had 4 notches.

With the small 1.78/1.50 stock heads the begin to flow Less over .400 lift anyway! Besides
which they will crash the valve into the piston much over that lift anyway with the engine blueprinted
to correct deck and head CCs!

I have been racing stock/SS cars for well over 60 years and help at the track for over
70 years. I keep very current on the rules and we have been torn down dozens of time
and always found legal. We are not popular with the small block GM and Ford guys we compete
against and beat regularly.

BTW: We spend $100,000.00 plus Researching/Developing and
Racing these cars every single year for decades. I am pretty reliable if
I tell you anything I have found out despite my detractors on this site.
 
The Jaundiced GT (my '71 Dart GT) sports an Edelbrock LD4B intake (used $113 to my door) with an Edelbrock 1406 600 cfm carb (also used $150 to my door). I used new Lokar throttle & "kickdown" cables from SummitRacing.

Fresh Drvr Side (cropped).jpg
 
Millions of 318s came right from the factory with the 360 intake using the 360 sized ports on 318s. Chrysler didn't think much of the port mismatch. They ran fine. The engine is not capable of "piling air up" around the smaller head port, because the engine cannot pull more air into the port than the port is big. Chrysler knew it wasn't a problem and it never was. Maybe with bigger valves in the heads and ported heads, you might see an issue, but if someone does all that, they will probably upgrade heads anyway.
 
Last edited:
RustyRatRod said:
Millions of 318s came right from the factory with the 360 intake using the 360 sized ports 318s. Chrysler didn't think much of the port mismatch. They ran fine. The engine is not capable of "piling air up" around the smaller intake port, because the engine cannot pull more air into the port than the port is big. Chrysler knew it wasn't a problem and it never was. Maybe with bigger valves in the heads and ported heads, you might see an issue, but if someone does all that, they will probably upgrade heads anyway.
Click to expand...
Agreed, I run a 360 cast iron spreadbore on my 318 head (1.74/1.50) Power-Wagon.
 
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67FormulaS_273HiPo_4spd said:
Remember that you'll need a decent twin system exhaust to take advantage of the 4BBL setup,
Click to expand...

This piece is already done, the truck has a dual exhaust already but was rusted to hell, had it replaced with a new dual about 3 weeks ago.

Just swapping the exhaust for one that wasn't swiss cheese seems to have made the truck run better.
 
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