Besides, it will a lot more streetable.

Sure, a 360 is a much easier path to 400hp......... but the op did say:
“.........anything over 300 would be great.”

And that shouldn’t be that hard to get to at all.

Especially if he’s willing to buy heads.

If you went with something like the EQ heads....... and down the road you get the urge for more power, the top end could be reused on a 360 or 408.

His first opening line of the thread:
"wanting to get close to 400 hp."


300, IMO is not very close to 400.

If he can change his target, he can also change his solution, IMO.

And the last line of the first post says anything over 300 is fine.

I would have no trouble hopping up a 318 and landing somewhere between 300 and 400hp, and not building a whole new motor to get there.

As always the intended application should dictate the path you take to 400 hp especially when you limit your displacement to 318.

Lightweight racecar only? W2's or better, big cam and set the shift light at 7200.

Not so lightweight street/strip car and street manners don't concern you? See above.

Daily driver heavy gotta get to work dependable? Budget type aluminum heads well prepped, factory type roller should easily get you 1hp per cubic inch without destroying street manners and then depending on how adventurous you are, a single turbo to easily surpass your goal or spray it.

My vote would be turbo if for no other reason than it doesn't need to be WFO to enjoy its benefits.

Kevin

if the guy wants to get that juice from a 318 let it be!!!! even more is it posible!!!! he has his reasons to work on his 318!!!!

shame the article about 318 400hp WITH PARTS OUT OF THE BOX is not anymore on line!

Copying from the HotRod Article:

Why build a 318? Some may argue there is never a reason to build the Mopar 318. When the time comes to rebuild a small-block, the 318 should always be cast aside in favor of a 360. We won’t argue. A 360–built properly–will always have a torque advantage over a 318.

Does this sound familiar around here ?, lets continue:

However, 318 cores are free for the asking, and that offers some economic incentive. But the real motive usually isn’t a matter of cost. The bottom line is like it or not, 318s are being rebuilt by enthusiasts every day. Some guys have a certain sentimental attachment to these cute little engines. sometimes it’s just the desire to retain the car’s original powerplant. And some guys dig the idea of blowing doors in with just a 318. Count us in that last group. We were intrigued with working out a combo that shows how to really make one run. Our goals were straightforward:



-The engine would be based on a regular 318.
-The engine must run on 91-octane pump gas or less.
-The camshaft must be daily-driver streetable, at least in a hot-rod sense.
-The build will not include any exotic, rare, unusual, or excessively expensive parts.
-The parts will be bolted on out of the box with no custom tricks, massaging, or porting.
-The final output would break the 400hp barrier.

and goes on... to THE BUILD.

I think the mopar mag article was built with diff parts

I guess I should have noted that this is a daily driver and yes I would love to have 400 hp but I know with the compression ratio that would be difficult. So anything 300 hp or over would be absolutely fine with me

Also I already have new long 318 block with 0 miles. I usually do go with 360 mainly for the torque. I’m just trying to make do with what I have.

I'm just noticing 3 members including me posted the hotrod mag link LOL.

there is a fact, Pistons must be replaced to reach close as posible zero deck

The 155 hp is factory rating which is typically a little low. My engine will now breathe a lot better with all of the emission restrictions removed, headers added and free flow exhaust. Also with fuel injection you can get the fuel ratio better which helps also. So assuming I’m somewhere near 200 hp is not implausible.

Some are paying too much attention to the 400 hp and not the thread title. Best way to increase hp in my 318

A relevant question is what year motor do you have, different years have different compression ratios and technicals.
Is it a later model 318 roller cam motor?

Alright, so you may already be near 200 but have not confirmed that. I'm not so sure that mopars have emissions hardware that really impede airflow, but if you have changed the intake and added a 4bbl, headers and duals, then yes, you have probably improved pumping capability.

Still recommend trying to find the cam specs, determine what casting heads you have, and taking a cylinder pressure reading. Knowing actual cylinder pressure is much more helpful than a published compression ratio. The factories have demonstrated a wide variance in actual ratios compared to advertised ratios. Knowing the year of the engine, as pointed out above, may help with this. All of these thing can help determine if a cam change or head change is going to be a negative or positive impact on cylinder pressure and power output.

If you don't mind throwing money at it, then you can just start changing things and backpedaling into the corrections to fix what you just changed. I'd recommend against this approach.

30 years ago I re-ringed a previous stock rebuilt 318.
675 heads with some clean up, 340 cam, std performer intake, headers...... dynoed it with a few different carbs........ best result was mid-290’s hp.
I’d have to see if I could find the sheets, but I think that was a 650dp on a 1” spacer and 40dg timing.
That thing really liked timing.

Better heads and cam would easily be worth another 25hp+, and then you’re solidly into the 300’s.

A few years later I was building 318 oval track motors.
596 heads, block decked/heads milled for 10:1cr, solid cam, roller rockers, stock 360 2bbl intake and a 500/2bbl Holley......... they were well into the 350hp range.
Multiple track and series championships with those.

This was the California emission variety. I did install 4 barrel aluminum intake with fitech fuel injection. I will look on the block and get the date I think it is a mid 80’s though

My recipe for the Waygun's tired 80,000 mile original 318 3 on da tree in the spring
Hone,re ring and reseal.
Using original pistons.
Summit K6900 cam,Cloyes Timing set,bumped up 4 degrees.
Eddy Perfromer spreadbore intake with 800CFM Thermoquad,Hedman Hedders
"Worked" 596 360 heads.
Hayes HD Street clutch set.
I already have dual exhaust,recurved distributor,and said mentioned Thermoquad (but on a 71 340 iron intake) exhaling through factory logs.

Not sure how much I will gain till I put the car on the Dyno.
Heavy wagon so torque is what I am after.
If I gain a few ponies that is also a plus
I am stoked and curious on how it will work.

Dizuster and his buddy ran a 70 Dart right out of high school. Bone stock 318 short block, stock LA style 360 heads, stock 4 barrel intake, T quad, headers with 2 1/2" exh. It had a Mopar performace .484 cam, (yes I know to big). Stock converter, 245 street tires (non sticky) 4.10 gear. would run 14.0@100 with no tire spin. Not a world beater. But cheap and it worked.
Doug

Since OP has zeroed in on a few concerns, such as using what he has, a 318, and the cost savings there of, in lieu of various other suggestions, true costs usually take into account final market value when completed, and eventually offered for sale, or parted, so, how much demand/market is out there for 300-400hp used 318's?

The engine is a 1984 so should be in the 8.6:1 ratio. I have called atk and gave them the serial number and a tech is supposed to call me back tomorrow to verify. I will also do a compression check when I get everything wired back up.

How to get 400hp out of your 318 in three easy steps:

1) Add enough nitrous to get you to 400hp
2) Run it until it blows up
3) Replace 318 with a built 360...

Replace 318 with a built 360... Not!

- EM