More power from a 318

[Chrispy]

Everyones opinion valued on this question. Im rebuilding my 318 over this winter and I want at least 300 - 350hp. Its going in next week to get acid dipped, crack tested and skimmed then im gonna smooth it down and paint it then reassemble it with new goodies  Here lies my question  What are the best mods for these engines ie, what manifold and carb setup, internals, extractors etc. Thought it might be easier to see what works rather than just buy what the man behind the counter wants me to buy. Big thing is that I want to do as much as I can myself. 

Thanks
Chris

[RTTT265]

More compression

KB pistons domed etc

Personally Im going to keep my intake runners 273/318 small and valves and stay with 318 heads.

[v43]

stroker kit 

[RTTT265]

http://www.lunatipower.com/ProductGroup.aspx?id=297&cid=87

If chasing big HP, go 360 heads and intake, valves, cam single plane etc I reckon

But if chasing modest HP I reckon go for streetability, throttle response, smalll port intake, duel plane, port velocity etc

   

[stefan]

I reckon a 318 is a great little motor for performance on a budget - heaps easier to get hold of than a 360 too. Mopar Muscle did a couple of articles on 400hp 318's all with bolt on parts. makes for good reading.

I ran 360 heads on mine, with a fairly large hydraulic cam. (106 deg lobe crs, 500 thou lift, 290something duration) one thing to watch with the open chamber 360 heads is getting enough compression - I had to deck the block 20 thou and take 40 off the heads just to get it reasonable.
I stuck with the 1.94 inlet valves too.

the first version of that engine had a victor 340 inlet manifold, 600 v/s holley, 2500 stall in a 727, went really well up higher in the rev range & sounded awesome. this time im going to use a performer dual plane for a bit more low down & an edelbrock 600.

Most parts are factory chrysler items - crank is a factory forged one, 360 rods, that saved  some $$ and they are plenty strong enough for the revs that I plan on pulling. Id say that the motor probably owes me 4-5k parts & machining and will be around 300 - 320hp

Or you could do what clint did & hang a dirty great big turbo off the side...............

[Chrispy]

Ha ha have toyed with the idea of a turbo or pro charger hanging off the side. Would fill the void made by the engine being offset in the engine bay. Thanks for the comments so far.

[valvebounce]

Get a set of KB pistons. (KB167's I think?)
Have your block (square) decked to yeild a zero deck height.
I too would stick with the factory small port heads. The larger port 340/360 heads have much more chamber volume, which kills the cocmpression ratio. follow this guide here http://www.forabodiesonly.com/mopar/showthread.php?t=167865 to free up some ponies. Chose a cam to suit your rpm range. If you go bigger than about 224@.050, you'll probably need a high stall converter to get the best out of your engine. A cam like the Comp cams XE262 is as big as you'll want to go on a stock converter.
Have your rotating assemebly balanced.
If you spend a bit of time reading up in the small block forum at for a bodies only, you'll pretty quickly get a handle on how to reach your power goals.

[Carlwalski]

Not too familiar with the 318s but search on here for "78Fury" as he did a nice little build (reliable and stout) on his 318ci V8 for his Fury. Have fun and good luck!

[78Fury]

Hi Chrispy, stroked my 318, just wanted an engine I could boot when I wanted a little extra grunt. I certainly got it.

2000 rpm (75 kph) 116.7 rear wheel Kw = 557.18 n/m torque or
2000 rpm (75 kph) 156.49 rear wheel HP = 410.96 ft lb torque

3000 rpm (115 kph) 166.7 KW = 530 n/w torque or
3000 rpm (115 kph) 223.54 HP = 391 ft lb torque

3200 rpm (125 kph) 170 KW = 507 n/w torque or
3200 rpm (125 kph) 227.9 HP = 374 ft lb torque

I'm quite happy never wanted a high reving donk or after high HP. the power is where I want it for a driver

Stroked to 4in
Weiand Intake Manifold 925-8007
Holley 600cfm carb w/vacuum secondary & electric choke 510-O-80457S
Holley chrome fuel line 510-34-150
Holley chrome air cleaner (14'' x 3'') 510-120-146
Lunati Voodoo Camshaft & Lifter 638-60401LK
Lunati 60401LK - Lunati Voodoo Hydraulic Camshafts
Voodoo Camshafts Camshaft & Lifter Kit Lift: .454''/.475'' Duration: 256°/262° RPM Range: 1000-5500
original 318 heads
1.88 inlets port matched heads and polished the chambers smothed out the short side guides and pockets.
1.6 roller rockers.

replaced Weiand 4 barrel with Demon 6 pack

could easily increase hp and rpm by fitting cam and extractors depends a lot on what you want.

cruise at 100kph just under 2000rpm. Original diff and box.

nice cruisy car till you put your foot into it and the other 2 carbs start sucking gas 

 

[RTTT265]

All of the above looks good to me,   I was close ........................  ha ha

[TK]

300-350 is pretty easy without stroking it, if that's not where you are going. I can say I love my 4" stroke 318... :)

To get 325HP, all you need is a stock set of 318 heads, a little bowl work, port match, stock valve size, or a bigger exhaust valve if you like.
Stock pistons, at zero deck.
Stock rods, crank, just have it balanced.
Stock pan, add a windage tray. (free HP)

Other adds would simply be a 500-600cfm carb of your choice, a small port single plane, or dual plane manifold, an offenhauser dual port is a beauty, and will make a 318 snappy. Some headers would help too. Or 360 manifolds.

Cam would be a 260ish adv duration, 450 lift, 106 or 104cl......

300HP, would simply be a stock 318, zero deck, with the cam, intake, carb, and headers, nothing special needed.

350HP, would require more extensive head work, etc.

Really, you should develop a plan on what kind of money you have, parts you have, or can afford, your capabilities, if you, or an engine builder is building it, if you are comfortable, or comfortable paying for porting, etc.

I know 25HP doesn't sound like much on the computer screen, but once you get over 1HP per cubic inch, HP gets harder to come by every little bit.

For example, a stock well tuned 220hp 318 from a truck I had, did the 1/4 in 20 seconds in a 5000 pound truck, 2bbl and all. 220HP, the time came out about right in the heavy truck from what I recall years and years ago.

I simply added an Edelbrock performer intake, and 600 edelbrock carb, took it back the next weekend, and it did the 1/4 in the mid 16's.... I remember the HP we figured math wise went up to 250HP. The motor also gained another 1500RPM of useable power. (with the tiny stock 248/248 cam)


My duster, had a stock head 318, with a offenhauser 360* manifold, stock compression, 600cfm carb, with the old 270/270 COMP (before I knew better) it ran mid 14's, I remember math said HP was somewhere around 300. (It WAS 15 years ago)


It took 3K worth of roller valvetrain, months of porting, and 8000RPM from that same 318 push that car 11.53. :)

So, think about where you are at with what you want, and we can help much better, instead of throwing builds, strokes, what ifs, and shoulda' coulda's at ya!

[valvebounce]

Measure how far below the deck your slugs are to begin with.
From what I've read, they can be as far down the holes as .080. On a motor I'm going to bolt together (IF I ever get the spare $$$ to get the heads done) I'd like to try to shave the decks to get zero. But on most of the forums, people tend to decry shaving the hell out of the block, in favour of replacing the pistons. The off the shelf KB pistons for the teen only necesitiate a minimal deck cut. (Or so I've read)

[Chrispy]

Man you guys are orrsum  thanks for the info so far. This is my first engine rebuild ever so I'm getting excited. I think ive got a bit of a plan now.  Very keen to stroke it so what is actually involved in doing this? Is it just a kit that you buy and install or does it re quire lots of machining, or both?
In regards to the rest Im going to clean and mildly work the heads, fit new manifold with a 670 carb (cant remember name but new to market from C.H.S in christchurch.) Will fit a mild cam with hydrolic lifters and a good set of extractors (any suggestions on extractors welcome) Just need more info on stroking ( ooh that sounds so bad) from you chaps. Right,,, now Im off to strip the engine down ready for acid bath and crack test next week. Ill start a build thread when I get the block back.

[78Fury]

Hi again Chrispy,

Imported my 390 stroker kit from Campbell Enterprises in the US. Eagle 4in crank and I beam rods,Keith Black stroker pistons forged step dish 030 oversize, main and big end bearings. Balanced rotating assembly. Machine shop in Napier checked block and 030 rebore. Also worked the heads for the 1.88 inlet valves. Everything else I did myself, was a lot of fun as I hadn't touched an engine for over 35 years.
Main thing to think about is what you want out of your engine.
If you just want to liven it up you could just add a 4 barrell, cam and extractors.                                                                                                                                                                                                 
I wanted power with economy and have that. Shes a real stump puller. There is heaps I could do to it if I want more HP and higher RPMs but I'm happy with what I got.

[Carlwalski]

For the record (and perhaps your peace of mind), like Graeme, I also used Campbell Enterprises in the USA.
I imported pistons, rods, rings etc for one of my old 340ci engines and they were top notch.