Quicky 318 rebuild: 300 HP dependably?

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MOPARdefiler

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New to mopar. ive got a 68 barracuda with a 318, mild cam, eddy performer I think with an eddy carb (600). It runs great, real ballsy for a small block, but i know nothing about it as far as mileagr, previous beatings/abuse or competency of the previous assembler. TIME FOR A REBUILD. Nothing exotic, nothing expensive.

I am thinking a stock, rebuilt bottom end with an .030 overbore, hypereutectic pistons, balanced assembly, a set of 340 J heads, the edelbrock performer and carb, and a set of basic cheapo headers. Having trouble with cam selection, but will soon be 4 speed and i think the rear gears are 3;70 ish.


Thoughts/ idseas/ experiences? please school me on the 318. Thank you.
 
Set of KB167's, find some 587 340-360 heads with 1.88 intakes (cheap and same as J heads) mill them to get the compression up. Comp makes some great cams XE268 XE274 are good ones. After swapping the heads that performer intake will have to go (runners too small) find a Eddy RPM, LD340, RPM airgap. Just my 2
 
Ran many of about the same combo in the past.
Depends on your piston.
Compression is your friend to an extent.
What are you going to do with the car, cruise, street performance.
With the gear you are looking to run ditch the performer manifold and eddy carb.
Run a good quality cam with around the same lift and duration as a stock 340 6-pack cam.
I always liked a single plane manifold and a 750 vac secondary holly on 318's that I built in the past, enough gas to feed the upper rpm's but no bog from the vac seconderys, but gas milage will not be that great.
 
Badart said:
Set of KB167's, find some 587 340-360 heads with 1.88 intakes (cheap and same as J heads) mill them to get the compression up. Comp makes some great cams XE268 XE274 are good ones. After swapping the heads that performer intake will have to go (runners too small) find a Eddy RPM, LD340, RPM airgap. Just my 2
Click to expand...


2x you just posted faster than me.
I think my buddy has a set of 73-74 360 188 heads for about $200,
they have been manuflexed. Just need freshend up.
 
Badart said:
Set of KB167's, find some 587 340-360 heads with 1.88 intakes (cheap and same as J heads) mill them to get the compression up. Comp makes some great cams XE268 XE274 are good ones. After swapping the heads that performer intake will have to go (runners too small) find a Eddy RPM, LD340, RPM airgap. Just my 2
Click to expand...

Spot on.....

Or some swirl port 318 heads and open the port runners up to a 340-360 window size for a more variety of intakes.... I purchased the comp xe268 but haunt installed it yet
 
Me personally I would put a gt45 turbo on it and never mind chasing rainbows and it would be as dependable as a stock 318. ANVIL LIKE!
 
Any good used 318 longblock will make a reliable 300 horse. Let the bolt ons begin. Compression and oil pressure is all you need.
 
needsaresto said:
Me personally I would put a gt45 turbo on it and never mind chasing rainbows and it would be as dependable as a stock 318. ANVIL LIKE!
Click to expand...

Id LOVE to turbo it BUT......This is to be a quicky hi-po rebuild. read: CHEAP.

I mean, with turbos, im looking at custom headers/exhaust, blow through carb, oil cooler, intercooler, expensive radiator upgrade, good heads, etc, etc.....really expensive stuff, and it just isnt that dependable as N/A in the long run. i need to drive this car dependably, as its our 2nd/3rd-ish family car. I wouldnt want to put that much money and effort into a small block that was going to get swapped eventually anyway.\


I DO plan on 2 hair dryers bolted to a 440 much later.....like after power tour next year.:glasses7:
 
sireland67 said:
Ran many of about the same combo in the past.
Depends on your piston.
Compression is your friend to an extent.
What are you going to do with the car, cruise, street performance.
With the gear you are looking to run ditch the performer manifold and eddy carb.
Run a good quality cam with around the same lift and duration as a stock 340 6-pack cam.
I always liked a single plane manifold and a 750 vac secondary holly on 318's that I built in the past, enough gas to feed the upper rpm's but no bog from the vac seconderys, but gas milage will not be that great.
Click to expand...

My plans? for now, its going to be a daily driver. thats why im keeping gears around 3:70/3:90 ish, swapping to stickshift for a little overdrive action, and trying to keep the carb on the small size. No drag racing yet, i want to pull down about 9, maybe 11 MPG while still being able to light the tires with ease if I want to. Its gotta idle somewhat reasonably, make enough vaccuum to run the brake booster,and its gotta be bare-bones simple to tune and work on. No 6 packs, turbos, fuel injection or complicated ignition/timing or wiring set ups. Its gotta be BASIC. CHEAP. DEPENDABLE. The budget and soon-to-be wifey will allow for nothing more at this time......however, if i could slip a set of forged pistons in there without her looking, I might be able to add a little N2O on the sly.8-):burnout:
 
You have to work hard NOT to get 300 HP from a 318 with 9.5 compression a decent cam good induction and headers.
 
StrokerScamp said:
You have to work hard NOT to get 300 HP from a 318 with 9.5 compression a decent cam good induction and headers.
Click to expand...
Really , headers intake and a good cam and you'll get decent mileage and be able to light the tires .
 
MOPARdefiler said:
Id LOVE to turbo it BUT......This is to be a quicky hi-po rebuild. read: CHEAP.

I mean, with turbos, im looking at custom headers/exhaust, blow through carb, oil cooler, intercooler, expensive radiator upgrade, good heads, etc, etc.....really expensive stuff, and it just isnt that dependable as N/A in the long run. i need to drive this car dependably, as its our 2nd/3rd-ish family car. I wouldnt want to put that much money and effort into a small block that was going to get swapped eventually anyway.\


I DO plan on 2 hair dryers bolted to a 440 much later.....like after power tour next year.:glasses7:
Click to expand...

I see your point about budget. Everyone has one and a turbo is extra $$ to do..BUT I was saying build a stock motor for like $1500 and then just add the turbo. This will get you well beyond 300 h.p and would be very dependable at 6-10 psi of boost. There are PLENTY of factory turbo motors out there and they last just fine with proper maintenance.

Yes you would be required to make oil changes frequently and on time.

Anyway it's just an idea and I understand you not wanting to go in this direction. It's easy for me to spend your money right?lol.
 
needsaresto said:
I see your point about budget. Everyone has one and a turbo is extra $$ to do..BUT I was saying build a stock motor for like $1500 and then just add the turbo. This will get you well beyond 300 h.p and would be very dependable at 6-10 psi of boost. There are PLENTY of factory turbo motors out there and they last just fine with proper maintenance.

Yes you would be required to make oil changes frequently and on time.

Anyway it's just an idea and I understand you not wanting to go in this direction. It's easy for me to spend your money right?lol.
Click to expand...

Really how much more would it cost ? I would go supercharger though , have had a few and they are very reliable and power is instant , but then there is the budget , have not priced superchargers lately .
 
MOPARdefiler said:
It runs great, real ballsy for a small block
Click to expand...

Why bother messing with it then? :dontknow:
If anything, just keep adding good bolts ons.
I mean as long as it's running strong who cares how many miles are on it or who put it together or beat on it already.
Since 318's are free from most people, if you're going to build one just get another core engine to do.
 
I have much the same in my 318. I used a Comp Cams XE268H cam. I am more than pleased with the power and sound. Get a good stall converter in there, too. That will do wonders for your get up and go.
 
daniel_depetro said:
Why bother messing with it then? :dontknow:
If anything, just keep adding good bolts ons.
I mean as long as it's running strong who cares how many miles are on it or who put it together or beat on it already.
Since 318's are free from most people, if you're going to build one just get another core engine to do.
Click to expand...

It's tired..
 
I guess I was left out of the loop, because the O.P. stated it "runs great" and is "real ballsy". Neither of which are commonly associated with a 318 that is "tired".
 
The basic things standing in the way of your horsepower goals are breathing and compression. For these reasons it is easy to over-cam the 18.

The J-heads will help with breathing but with larger compression chambers, they will hurt compression issues. Swapping to the J-heads will also require at least an Eddy Performer RPM (to stay in the product line) for the intake runners to match up properly.

Recommendations: Stick with what you have for the teen. Put some $s into a 3-angle valve job and hardened seats. Blow off the HP goal for this engine and save the good stuff for the good engine. I'd recommend a cam, but need to know compression and rear gears.

For a family car, 3.70-ish is too much gear IMO for high way use. Suggest 3.23-3.55:1 range.
 
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