318's are great engines, and highly underrated by a lot of folks. That being said, 400 hp is not easy to do with a 318. At the very least the stock heads are too restrictive for that much power, so you'd need a ton of head work to get to 400 hp, with high compression and a big cam. It would not be super street friendly. Stock the 318's made from 175-230 hp, depending on the year of manufacture. The later one's suffered from low compression and smog alterations to timing and carbs. If you need pistons already that's a great way to add some power, and make sure you check your deck height before you decide what to get. 318's are notorious for having the pistons further down in the hole than the factory said they were, so some had really low compression. If you want to do better than the stock heads without spending the money on aftermarket look for 89-91 "302" heads. These are closed chamber heads with 318 size ports, and were found on trucks/vans with 318's in that period. The exhaust port design is the same as the performance W2 heads, and flow well even in stock form. They also made 308's in this time range, but they were for 360's and have open chambers and larger ports, which slows intake velocity on the 318's unless you're shooting for big power. The 302 refers to the last 3 digits of the casting # on the head. The nice thing about the 302/308 heads is that they are LA heads, not Magnum heads, so you don't have to worry about the lifter oiling thing changing over to Magnum heads. A 318 with 302 heads, 9 or 9.5:1 compression with a performer rpm intake, 600 cfm carb, headers and a nice cam should put out a good 300 hp without issue (or more depending on how crazy you go with the cam), and still be very streetable. But without head work it'll be real difficult to get much more than 350 hp.
Horsepower. Everyone is concerned about HP#s. Its the torque you want on the street. 318s have great low rpm torque. Dual exhaust, even with factory manifolds, and a 4bbl carb & intake really wake up a 318. Add in a small cam, (with a working rpm range of 1500-5000) or even a factory style 340 cam and you bring to life a whole new critter. Keep in mind the actual rpm range your 318 will be running, most "improvements" only increase the working rpm range. The stock 318 heads and ports work well up into the low to mid 4,000 range (on a 4500-4600 factory intended red line), how often are you planning on turning it that high? Real life experence: Stock 318 block bore & stroke, fresh rings & bearings. Stock 318 heads match ported to the intake and exhaust gaskets. A factory iron 360 4 bbl intake, factory 318/360 exhaust manifolds (mid- late 70s truck center dump) dual 2" exhaust to the rear bumper with turbo mufflers. Comp 260 cam, Mopar electronic ignition mated to a 904 and an 8 1/4 rear with open 3:55 gears (later changed to 8 3/4 with 3:23 open) in an all steel full fendered 35 Dodge 2 door sedan. Car could spin tires (255 60 x 15) at will from a standing start, pull down 20 mpg @ 70mph with power to pass and could run down the road with most anyone. We put 66,000 trouble free miles on the car in 6 summers, then sold it to fund the next ride. The hard core chevy guy that bought it was impressed with how much power the little 318 had. It was hard to convince him it was "only" a 318. Gene
a quick reply...the 318 I bought from a friend was 50 bucks!!! two years and 8,000 miles later in my 30 ford 5 window Rat Rod !!! I dig it, being a chevy Dude, my friend forbid me puttin a 350 chev in it, hence the 318. I spent 450 bucks on a rebuilt 904 and new converter, DONT forget the Lokar kickdown cable, or you will burn up the trans.It runs Absolutely Awesome and takes me anywhere and always starts up , I swapped the intake and put a junkyard Q-jet on it. the stock cam has tons of torque!! Later "Race"
i have been a mopar guy all of my life, and have to disagree with the mp purple shaft cam comments.. although the magazines push them on most of their builds, i personally think they are the worst cam you could buy for any mopar engine .. i have tried them in a big block, small block , and even a slant six and every one of them was terrible on power. the best luck i have had was with comp xtreme energy cams and the crane cams (not the magnum cams, the dual grind series ) just my 2cents doug
318's are great for cruising and pep. my 67 fury has the one it was born with and it moves that boat around fine,with the 2 barrel on it and 21mpg. Same with the 37 hudson it runs a 73 out of a dart.The tranny to get would be a 727 torqueflite or overdrive out of a f-s pickup or a dakota.So cruising or hot rod it will work.
I'll second that. The purple shafts are old grinds, and there are a lot better, more modern grinds out there nowadays. I prefer Hughes because they are low duration, high lift.
Most of the advice here is sound, the only thing I have to add is if you run across an old edelbrock LD4B intake at a swap or somewhere, they're an excellent dual plane that lends itself to what you are shooting for. They're basically a small port version of the well known LD340. The newer manifolds will flow a tiny bit better, but I'll bet the difference is not even measurable on a mild 318, and they can usually be had for 100 bucks or less.
400hp out of a 318 is actually pretty easy, and cheap! Rebuild the 318 with a stock bottom end, exept for pistons and rod bolts. Get some KB's that get the compression up. Then go get a set of Magnum heads from a later model 360 Magnum, pocket port them, and bolt them on. They have 1.92 intakes, 1.60 exhausts and small chambers - you want to shoot for around 10:1 compression. You will need to use AMC lifters because the later mopar small block oil through the pushrods, and the proper pushrods. I like to run roller rockers, and you use a standard small block hydralic flat tappet camshaft. I would use the Isky Megacam 280. You will need a magnum intake since it uses a different bolt pattern - i like something like a Performer RPM with a 750 carb, and headers. Voila - 400 hp. There has actually been several articles about this combo. It works really well, and the late model Magum heads are key. It like putting Vortec's on a SBC. Cheapest good running combo? Get a bunch of 340 parts and bolt them on - Cam, springs, timing set, intake, carb, and a set of headers. On an early 9:1 compression 318, this is an easy 275hp combo. You can get about 350hp using the old style heads with the same combo.
Honestly, I was told by the guy that sold me my donor that it had a 318 in it.... I went out and bought a 4 barrel intake rear sump pan etc and then I ran the numbers and it turns out its a 360.... well all of the 318 parts are on my 360.... the only difference I was told is the part numbers.
Part numbers aren't the only difference!!! The oil pans are different, so I can guarantee you if the oil pan fit it wasn't for a 318, or you don't have a 360. One will not work on the other. 318/340's share a pan, 360's have a different sized radius around the main caps. Intake manifolds will fit, but there are two different intake port sizes, one for the 318 and one for 340/360's. The intake will fit, but if it truly has 318 size ports they will be smaller than the intake ports on the head. This depends on the intake though, a lot of "318" intakes actually have the larger ports because the manufacturers are lazy and stopped making 318 specific intakes awhile back. Other than that, 318's and 360's have a completely different bore and stroke, different sized mains, a different engine balance (318's are neutral, 360's are external balance), and the heads have different sized chambers and port sizes. Figuring out which you have is easy on a mopar, you don't have to run the numbers as the displacement of the engine is stamped on the side. For example, my 340 As you can see, the "340" appears clearly at the end of the casting number on the driver side of the block. Here are a couple sites with some good info regarding mopar engines... http://www.mopar1.us/tech.html http://www.mymopar.com/index.php?pid=31
When you bring the piston up to zero deck clearance, you not only increase compression ratio, just as important, you increase "squish" (quench) which stimulates lots of air/fuel turbulence toward the end of the compression stroke as the spark plug has already initiated the combustion cycle. Combine this with the closed chamber "high swirl" combustion chamber, you dramatically wake up the "LA". Here is what small block chevy guys pay big dollars for that come stock on the "LA". 1. Direct oiling to crankshaft. 2. Long con rods - 6.123" to sbc 5.7" 3. Tall deck - 9.6" to sbc 9.025" 4. High camshaft location to accomodate long stroke cranks 5. Shaft mounted rockers 6. 18* valve angles 7. Valves centered over cylinder diameter - less shrouding than sbc 8. Spark plug location closer to center of cylinder - less spark lead required 9. Large diameter lifters allow cam grinders to profile more area "under the curve" 10. Positive cam thrust plate eliminates axial cam walk 11. All "LA"s come with gear reduction starters - almost trouble free. As has been mentioned before, and is a very good idea for any of the center sump oil pans, is to weld a sheet metal ledge (baffle) to the rear upper edge of the sump - it keeps oil in the sump around the oil pickup screen on hard acceleration. It only takes 5 - 10 minutes to do and is cheap insurance. After all, yer a hot rodder, arn'cher? Yer gonna stuff yer foot in it every now an then. Be sure to check stem to guide clearance, "LA"s are notorious for wearing guides, especially the exhaust guides. I think you're into a sweet project here. Keep all of us posted on your progress.
Generally, people building 318s "to be different" find out after spending $1-2,000 that they could have simply bought a stock 360 and had more power for less money. If you don't want more power, put it back together and drive it. A Ford flathead with the same power as a stock 318 costs $$$$$$$$$.
If you can get an el cheapo 360, go that way. They have way more torque than a 318. enough to really make the swap worthwhile. I appreciate that you already have the 318, but from my experience, its worth looking for the bigger engine.
I'd be careful about that bullshit when making generalizations about the Rodney Dangerfield of small blocks. Your 302 analogy is a little flawed because the 318 has more stroke than the 327, 3.31 verses 3.25. That stroke similarity and similar size displacement, given the other parameters are comparable, would give you engines with similar torque curves. I don't remember anyone in the 60s, 70s, and even 80s that was running a 327 really complaining about the lack of torque. Remember when the Chev race heads were first released with the "special" valve angle? Compare that valve angle to any LA head. See any similarities? As stated above, use pistons with a true zero deck, pick the right cam, add the right freshened up junk yard heads, and you should be able to more than match any factory 327 torque and horsepower rating. Difficult to pick the right combination, maybe, but that 400 HP level is probably doable without totally destroying all the streetable torque too. As far as "what's left?" Pistons and cam are usually changed out when rebuilding anyway. I don't know of very many people wanting to rebuild a motor without freshening up a set of heads, so WHY NOT do a set of readily available junk yard heads with real horsepower potential instead of the lo-po originals. The average bear adds an aluminum intake and four barrel carburetor at the same time if not before, as a matter of course, as much for the "wowing the friends" factor as it's real contribution to power output. Ditto on running headers. Run the stock bore and put a 4" arm in the basement, you'll get a 390. Sonic check the block, run the bore out to 4", and you'll have a 402. Admittedly, if you don't mind the 3" mains, using a 360 block saves sonic checking the block, but the possibility of nearly 400 CID is still there. Sorry for rambling, I just get tired of hearing how superior other engines are and how you shouldn't expect a 318 will perform.
well said. my 318 powered 4 speed 64 barracuda was the fastest car at my school and noone believed that it was a 318.. (especially all the kids that parents bought them 5.0s and newer camaros)
see the links I provided, and try again. its all in your time vs money the hot rod builup was $1,466.83 and netted 406hp/408tq http://www.hotrod.com/howto/113_0304_318_small_block_build/dyno.html
One thought - CAR CRAFT has an article that basically verified something I've seen several times in person - the '70s 318s have wall thickness to go out to 4.00" bore. So, you get a 4" stroke iron crankshaft for the 340 mains, use your stock rods, get a set of KB pistons for a 4x4 engine, and you've got 402 CI out of your 318 block. That's the way I'm going with mine. The benefit to it is availability, and there is slower bearing speed with the 318 due to smaller mains.
The early "A" Poly 318s have enough wall to stroke & bore to 402, don't think you'll find an LA that will.
a few notes.. first off the 175-220hp is correct.. It really depends on what you want.. want a cruiser put an aluminum intake and 4 bbl on it and some nice valve covers, paint it and be done. I'd say run nitrous for some extra kick but with that low C/R its not gonna be worth it. and a word of caution, If you do run an A500 / 518 / 618 make sure to not run a full 12v to the lockup and OD solenoids.. they are meant to be controlled by the computer with arround 5v I believe
53 sled, I was back at the beginning of this thread,,,and was made to look like an idiot,,so I didn't mention the article you were talking about. But,,you are right on target,,,a great build up that was not expensive,,just well thought out. Tommy
The 318 is a great engine,,and you don't need the stroker crank either,,unless that is just something you want to add. The power is there if you want it. Tommy
Mine clearly says 360.... also, Im assuming that the parts counter dude slipped up and grabbed me a 360 oil pan. Lucky me
This is great news for me. I bought a 69 Monaco that has a rebuilt 318 with aluminum intake,Holley carb etc. Rebuild tag shows mains and rods at 0.00 and the cylinders at .030.I,ll be pulling the motor and trans to sell at a swap meet.Guys don,t usually go for a 318 but maybe I can peddle it and buy something I actually need.
How about a 78 360 with Performer and 600 Holley, stock duals and a little over modest cam for H.P.? Any clues?
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