Help with building a bit more power in to the 318

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NorthernSwede

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Hi all!

My newly bought '66 Dart came with a freshly built 318 with the following specs given to me by the previous owner

"10:1 pistons"...
Stock camshaft
Stock rods
Holley 650 DP
Stock 360 heads
Stock 360 intake
Stock 360 headers


Problem is. It's sucking water into the oil so I'm going to tear it, and in the process probably changing the camshaft. But I would like to come closer to 400 horse, but nothing to wild since it will be running in front of a stock 904 with a stock 8.75.
So what would get me there? I've read the "400 horse 318" recipes that circulates round the web, but one of them uses 360 magnum heads and the others 318 heads.
So my questions are :

Would zero-decking, milling of the heads to get a true 10:1 compression, gasket-match porting, A quite mild camshaft


(something like the

Grind Number: 272 H10Operating Range:1800-5200 RPMDuration Advertised:272° Intake / 272° ExhaustDuration @ .050'' Lift:216° Intake / 216° ExhaustValve Lift w/1.5 Rockers:.454'' Intake / .454'' ExhaustLobe Separation Angle:110°Max Lift Angle:105° ATDC Intake / 115° BTDC ExhaustOpen/Close @.050'' Cam Lift:Intake - 3° BTDC (opens) / 33° ABDC (closes) Crane Cam)


get me close? Any more ideas?
 
If it were mine, i would just pull it & tear it all down, doing a leakdown will just pinpoint the problem, but it'll still need to be tore down anyways because water leaking in an engine most of the time is a bad & serious issue, plus you want to build it up anyways, tear it down to the last nut/bolt.

If you want 400 horses out of that 318 & do not want to stroke it, you'll need to spend some $$$, you need to get above the deck or have a quench dome piston to acheive close to 10.1 on a stock stroke 318 useing 360 open chambered heads, thats where the closed chambered magnum heads help, you can get there at or close to 0 deck & a FT, there are a few on these boards running really fast with "stock stroke" 318s.
 
So what kind of power could you expect if I ran it the with the above tweaks? Ofcourse the water problem is beeing taken care of, that's the whole reason for tearing it down. Sure but according to those "400 horse 318" articles. One of them were using 302 heads, wich of course have smaller chambers and so on, would I be better of with a pair of 302's with 360" size valves and porting?
 
NorthernSwede said:
So what kind of power could you expect if I ran it the with the above tweaks? Ofcourse the water problem is beeing taken care of, that's the whole reason for tearing it down. Sure but according to those "400 horse 318" articles. One of them were using 302 heads, wich of course have smaller chambers and so on, would I be better of with a pair of 302's with 360" size valves and porting?
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Don't know what size valves come on the 302 heads, but i'm sure they'll be plenty big enough for the 318, you could run some FT pistons close to 0 deck (shoot for 9.5.1), a nice cam/intake/carb setup, headers, good exhaust/ignition, this should make for a decent strong running 318, but with that said, for the $$$ spent you could just get a 360, unless your really wanting to stay with a 318.
 
Thing is, I'd like to cream some more power out of the things I have, really just looking at buying a camshaft. Machine work is no big problem since my best friend owns a mechanical workshop. So again, what am I looking at in power if I just optimize the setup thats already there. Meaning working the heads and carb. The DP should easily provide enough juice.
 
Firstly, sounds like you have either a head gasket problem, or more likely a pinhole in the bore. This can be fixed by sleeving the bore/s. I don't think you will get 400HP out of a 318 just by putting in a cam and port matching the heads, you'll need to spend some $$. The new aluminium heads are very well priced now, compared to reworking the old cast iron heads with all new valves, springs and heavy port work. For the bucks, they are the best dollar performance value bolt on. And you can still do more port work to the aluminium as well. Plus you would have to be going with a big cam, a roller hydraulic or solid cam, single plane inlet such as a Victor 340, forged pistons, balanced and blueprinted etc. You would be more reasonable to expect 300-320 tops for what you want to do and spend. AND are you sure you want to use a stock 904? They are a good strong box,but nothing liek a 727...A few heavy right foots and it will not like it.
 
A stock 904 will handle a mild 318 any day, i ran a mild 904 behind a fairly stout 370 cu. 360, there are lots of guys running really fast with 904s, they can be built up to handle the task.
 
Oh yes, i agree -the 904 will handle huge power when built properly. They are often favoured in drag racing over the 727 due to their lighter weight and reciprocating mass. I also am running a mild 904 behind a mild 360 (215 RWHP) in a heavy Challenger with no problems (although i don't abuse my cars)

i am just saying to Northernswede that it would not be advisable to put his stock 904 (which i assume has done some miles already) behind this 400HP 318 that he wants to build. Would you advise that? I don't think anybody would.

However if i had lots of of time and money on my hands it certainly would be interesting to put a new/rebuilt but completely stock 904 behind a well worked SB and see how much it could actually take.
 
pressurize the cooling system and pull the plugs.
Roll the motor over by hand while the coolant system is presurized.
you might be able to see if it's a certain cylinder is filling up with coolant or if it's a block leak by the crank case filling up with coolant.
Drain the oil and keep the plug out.
This is good info. to have before a tear down.
It might just be a blown head gasket.
As far as 400 horse out of a 318, it's a very good concept, but if you dont have the drive train combo to back it up, it will be a dog.
LIKE \NO GEAR\LOW STALL CONVERTOR=SLOW.
A 400 HORSE 318 WANTS GEAR AND A HIGH STALL CONVERTOR AND A LIGHT WEIGHT CAR.
good luck :tongue3::coffee2:
 
T67POWER said:
As far as 400 horse out of a 318, it's a very good concept, but if you dont have the drive train combo to back it up, it will be a dog.
LIKE \NO GEAR\LOW STALL CONVERTOR=SLOW.
A 400 HORSE 318 WANTS GEAR AND A HIGH STALL CONVERTOR AND A LIGHT WEIGHT CAR.
good luck :tongue3::coffee2:
Click to expand...

Yes. The oil/water mixing needs to stop first.

I agree with T67. A 400 HP 318 will be soft off the line without some cooperation from the rest of the drive line.

FWIW: The 302 heads have 1.78 intake and 1.50 exhaust valves like every other 318 except the late Cop Car 4 bbls.
 
if i wanted that much power on a budget, i'd find a 360 shortblock and go from there.
 
You can use the 360 heads, But you'll need to have your block zerodecked and use K,B. 167 pistons and you'll need a dual-pattern cam like a 484-474 lift, Itried the stock heads and the 302 heads on my 318, but i ran my fastest times with the 360 heads mine have 202-168 vavles installed, Everybody said the 302 heads would be better than the 360 heads,But i went from a 9.28 to a 8.87 in the 1/8 mile.I think as long as your engine is zerodecked that the 360 heads are the way to go I feel that i proved this by trying all 3 sets of heads
 
Hmm all of this made me think! I will think some more though and see what I can come up with at the time being, since I will be buildiing a 408 sometime during next summer it kinda feels dumb to spend a lot of cash on the 318!

And just for the sake of it, the 904 has run less than 500kilometers since total overhaul :)
 
NorthernSwede said:
Hmm all of this made me think! I will think some more though and see what I can come up with at the time being, since I will be buildiing a 408 sometime during next summer it kinda feels dumb to spend a lot of cash on the 318!

And just for the sake of it, the 904 has run less than 500kilometers since total overhaul :)
Click to expand...

I didn't think it was dumb to play with my 318's........ There had been 408's that are slower. If it was me? 4" the 318, you get a 390, and I personally think you get a better stronger block.
 
Isn't 400HP getting a little steep for the 318? Northernswede says he doesn't want anything too radical, but, 400HP in the 318 is pretty radical.
 
you can make a 318 pretty stout. it might not be no 400hp. but for now it`ll do anything you want it to.

and if you are looking for big numbers. you`ll end up spending some big numbers. ive got a 360 with stock pistons, about a 500 lift cam and some head work. and it does plenty for me. for now.
 
NorthernSwede said:
Yeah I thought of the 390 at first but noone seems to build them and i figured it must have a reason?
Click to expand...

Only cause most have access to a 360 and well..stroker pistons are cheaper for the 4'' bore than the 3.91 or 3.94, 3.95 etc....

If all I had was a 318, I'd build a 390 something cid in a heart beat.

Thats still a lot of inches and built right would smoke a lot of other motors out there.
 
So it will actually be cheaper for me to build a 390? Everyone seems to claim the opposite, but then again maybe they don't have to pay 600 USD for the 360. And yes, according to the PO the engine is freshly rebuilt, anyhow it runs good and has good compression ratios.

How much power will a 727 hold up to if driven HARD
 
You don't live in Sweden my friend! And sure I could probably find one for a hundred less but then again I rather pay more for good parts than less for ****.
 
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