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318 question

8K views 27 replies 7 participants last post by  eW3UAAg6OCk6j6 
#1 ·
i have a 87 ramcharger 4x4 with a 318 and 2 barrel holley. i am wanting to change it to a four barrel but have heard mixed ideas. is it true you can just throw on a 4-barrel intake and carb and b ready to go. i have heard that you have to change the heads for better breathing if not your motor wont breath right. wat is need to swap in a four barreloutside of the intake linkage and carb and of course your gaskets.
 
#2 ·
well you could just swap on a 4 barrel intake and go.  The problem is the factory cast iron 4 bbl intake has larger ports then the 318 head.  Many have done this swap and it runs but isn't the best way to do it and may cause it to run rich.  You have 2 options.  one is replace intake with Edelbrock performer which has smaller 318 size ports.  The second is replace the heads with 360 heads for better breathing but the 360 heads will cause you to lose compression so you need to mill the 360 heads to get your compression back.
 
#5 ·
son of ram said:
so if i put on a 318 specific 4-barrel intake im fine?
Only if it's a manual transmission. If you convert the 2bbl to 4bbl with any manifold, you'll need to address the kick-down linkage for the A727 transmission. Most go with the Lokar cable setup.
 
#7 ·
son of ram said:
its a auto tranny so . so i dont need new heads if i go with a edelbrock intake? or can i pull one off a junker?
Since it is a auto tranny you will need the kickdown linkage as previously stated(Lokar etc). The edelbrock intake will have ports that match up to the 318 head so you are correct.
 
G
#8 ·
The Edelbrock Performer is 50-state legal swap. It fits the 318 head ports. The Performer is the de-facto standard 318 upgrade for general step-up to 4V performance. Another great 4V intake, largely in the shadow of the Performer is an older unit called the SP2-P from Edelbrock. I used one with great results on a 318 with a only a twitch hotter than Mopar's RV cams (CompCams High Energy 260). It'd still yank the secondaries open on the Edelbrock 750 AFB without bogging, had fantastic low rpm power, and the old girl would average 19mpg as long as I didn't live with the secondaries open (single point type ignition). And I drove the crap out of it. That was in a '69 Charger (3,800lbs) pulling a stock converter and 2.76 gears. The SP2-P makes even more sense with the stock 318 cam. The narrow runners really slam the cylinders full for great throttle response and a full low to midrange torque curve. The intake worked so well, I still have it some 18 yrs later. Eventually, it'll be on another 318. If not the SP2-P, definitely get the standard (not Air Gap or RPM) Performer.
 
#9 ·
I have the Edelbrock Performer series intake manifold and an Edelbrock 1406 carb.  Works just fine.  There's a little lag on mine when you kinda get on it to cross a street with cross traffic, it bogs a little then spins the tires.  I think it may be timing....not sure yet.  Good setup though.  I'm only 2 turns out on both air/fuel adjusters to save on gas (a little).  Ran better when it was a little richer.
 
#11 ·
also egr or no egr? im sure mine is a egr but can i remove that and any other emissions crap. i really do despise it. id like to get rid of some of it as long as it dosnt hurt perfomance or driveability since this is my daily driver as of now. if ne one as a basic bolt on plan for a 318for more power that would be appreciated.
 
#12 ·
check the engine FAQ section it explains a 300hp and loads of torque outline using factory head castings a mild rv type cam ect ect.

if you have access to a 360 4 barrel sure go ahead and drop it in. they re pigs IMHO though.
 
#13 ·
son of ram said:
also i have been told that i should just swap in a 4 barrel 360 rather than a 4 barrel 318. any opinions?
If you look up manifold cast numbers many were used on both the 318 and 360, for instance 4173915, 4323352, 4100340 were manifold cast numbers used on 4027163, 4027596, 4323302, and 4772576 heads. In 80-83 head 4448308 (a predomately 360 head) was used on some 318 truck applications. A cast iron manifold weighs about 55 #
 
#15 ·
my 318 is original motor in my 87. but am thinking that a edlbrock power pack( cam lifters intake and carb) mite go that route. i do have a 88 360 with a 4 barrel ive been thinking of swaping in but that motor has 160k on it. not sure what i want to do.
 
#16 ·
joe swinehart said:
i see you have #302 heads and #308 heads in that list.

i was under the impression #302 was a 86-87 318 2bbl and 88-91 318 tbi head ??? and also thought #308 was a 360 tbi head ???
Joe,

http://www.nhra.com/tech_specs/engine/

The LA 302 and 308 truck heads have been around since 1980. 1989 was the last year for the 302 and 1992 was the last year for the 308 heads (and the LA engine series for that matter).

The predomate OE TBI manifolds were cast numbers 4201120 and 4323352 (up to 1989, after that NHRA has them as not listed for 90 thru 92)
 
#17 ·
I have a 88 318 4bbl sitting here at my shop. It is complete intake to pan, does not turn over by hand. I'm in IL. You can have it for $100 as I have no use for it.

Your a week late as I was just in KY on Sunday.

Let me know if you interested. eric@patriotperformanceauto.com
 
#19 ·
son of ram said:
patriot. what kinda mileage does the motor have on it? how long has it been sitting? any idea of the power its producing?
It has been sitting a long time. would only be good for the block, heads and intake. Would certainly need a valve job.

It was in the back of a 80 D-100 I bought. That all i know about it.
 
G
#21 ·
OhPinions said:
Joe,

http://www.nhra.com/tech_specs/engine/

The LA 302 and 308 truck heads have been around since 1980. 1989 was the last year for the 302 and 1992 was the last year for the 308 heads (and the LA engine series for that matter).

The predomate OE TBI manifolds were cast numbers 4201120 and 4323352 (up to 1989, after that NHRA has them as not listed for 90 thru 92)
You're mis-interpreting the NHRA docuument. It was originally written 1980, but revised several times: 5 Nov 1989, 2-16-96, 7-1-96, 2-16-98, 01/28/00,8-22-02,5-13-03. The 302/308 listing was added in a later revision. The 302 head was 1987-91, the 308 head was 1988-92, as plainly stated in the Mopar Performance LA engine manual.
 
#22 ·
gen1dak your correct but MP is wrong.  I don't know why they say the 302 heads came out in 87.  They actually came out in 85.  I've found plenty of 85 and 86 Diplomats in the junk yard with 302 heads.
 
G
#23 ·
Yeah, I have seen the same thing. an I remember the "new for '85" headline back then speaking of the "fast burn heads". I noticed something MP stated about how , on the 308 head, for example, casting numbers and part numbers changed, but they were the same thing...blah, blah, blah, so there's no telling just why. Maybe it has to do with the context of the reference to the engine's application to vehicle types. The 318 fast-burn was introduced first in the cars in 1985. They introduced them to the trucks later ('87ish?), and the 360 ('88ish?) fast burns came into truck use a year after the 318 fast burns?
 
#24 ·
I'm wondering why NHRA would list the 302 heads on pre-release 80-84 truck engines. Same for some of the late-70's car engines.

Someone care to take that on?
 
#25 ·
gen1dak said:
Yeah, I have seen the same thing. an I remember the "new for '85" headline back then speaking of the "fast burn heads". I noticed something MP stated about how , on the 308 head, for example, casting numbers and part numbers changed, but they were the same thing...blah, blah, blah, so there's no telling just why. Maybe it has to do with the context of the reference to the engine's application to vehicle types. The 318 fast-burn was introduced first in the cars in 1985. They introduced them to the trucks later ('87ish?), and the 360 ('88ish?) fast burns came into truck use a year after the 318 fast burns?
I have a 85 318 truck motor laying in pieces on the shelf and it has 302 heads. 85 was kinda a big change year for the 318. They got higher compression pistons that year along with the 302 head and I believe its the first year for blocks with roller cam provisions.
 
G
#26 ·
OhPinions said:
I'm wondering why NHRA would list the 302 heads on pre-release 80-84 truck engines. Same for some of the late-70's car engines.

Someone care to take that on?
My guess would be that the 302 and 308 are on "pre-release" spec sheets is because they are actual production engine heads, and would appear to be acceptable to the ruling body. The truck specs, even the 1980 list, was actually released in 1991, so it would initially include all head designs to that point. Even a 1970 318 block will run a 302 head. All the spec sheets, as I already mentioned, have several date revisions, presumably to address newer OEM castings as they were available. That way, someone could mix and match heads and blocks without rules infractions. They could use newer designs and still be within the rules, particularly if an older version of the head was no longer available.
It's either that very reasonable explanation (something along those lines), or perhaps you have a time machine, and have gone back and seeded 302 and 308 heads in 1970 smallblocks to alter history and give Chrysler a leg up on everyone else, and now you're asking the question to point out what you did.
 
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