Im kicking around the Idea to build up my 318 instead of building a Stroker 360 to a 408 . Money would be the only reason I realize there is no replacement for displacement and the torque and horsepower I would get out of the 408
There is nothing wrong with a 318 except compression, or the lack thereof. They have the pistons stuffed so far down in the holes that compression can be as bad as about 7.5 to one. Going with a good flowing head with tight chamber really wakes these engines up big time. Shoot for 9-9.5 to 1 or so and you'll be very surprised at the results.
Yep and blew his doors off But like mentioned above, there are ways to wake them up. It's just that they aren't as desirable as say a 340 or a 360. Depending on how many ponies you are wanting to squeeze out of it, like all engines, that will determine how much machine work and cash you want to through at it.
I don't know what a 408 is, but I've had some fun rides in a 340 dart back in the day. (1970) They will run just as hard as a Chevy or a Ford, might cost a little more due to supply and demand of parts.
The stock 318 2bbl automatic's I remember around the stip were 18 second cars (maybe 17's on a good day). That's just cars driven in off the street (not prepped for NHRA competition). They may have been a lot heavier than the o/t cars you are referring too? --- Steve ---
If I'm not mistaken, the 408 you referred to is a stroked LA318 engine. Otherwise, the rest of the guys are right. It's a low-po grocery getter motor. You would need to jack the static compression up, use a decent flowing head, and drop in a cam that works with the compression. Roger
Friend had 318 with 340 heads in high school in a 73 duster. Ran great and you could not kill it..we tried like hell.
Hughes built a 318 that made well over 600 hp ( closer to 700) with a Paxton supercharger. Almost 400 with the supercharger belt and regular carb
Hughes built a 318 that made well over 600 hp ( closer to 700) with a Paxton supercharger. Almost 400 with the supercharger belt and regular carb
Probably talking about a 360 stroked to 408 Are you talking about a 318 LA or a Poly? LA: In Australia they had nothing bigger than the 340, & few of those. They turn down the mains on a 360 crank to get 349, lets them run with the Ford Clevelands. The '62 & up Polys can do the same crank trick & they take a big overbore (with sonic check) that can go out to 402. Crank trick doesn't work on the '61 & earlier 318 Polys, but the big overbore is still in play.
Some of the later ones could be pretty hot for what they were. My father had a 96 Ram that was exceptionally strong, all things considered. He was always burning the tires off of it.
The 318 can be made to have some good power Mopar muscle built one that has 400 HP and I think they did more work to it and got more out of it. The 340 heads will bolt onto a 360 I'm not 100% sure they will on a 318. I do know that 440 heads will work on a 383 car, that is what made it a magnum motor...I hope my memory is correct on that. http://www.moparmusclemagazine.com/techarticles/mopp_0409_318_engine_build/viewall.html http://www.moparmusclemagazine.com/...8_small_block_budget_build_part1/viewall.html http://www.mopartech.net/showthread.php?t=2556 http://www.popularhotrodding.com/enginemasters/articles/mopar/0667em_mopar_318_engine/viewall.html http://www.hotrod.com/howto/113_0304_318_small_block_build/viewall.html There is more if you google. There is a few Mopar sites A and B body only that build these motors up. A few guys even tell ya to build them over a 360. Good luck and keep us posted and also the 318 there are a lot of them out there so that helps in getting a budget motor or a running car.
I did one up pretty good for a Challenger resto I did - it woke up real good with a Mopar Purple stick, performer intake, Thermo-quad carb (they run great when properly cleaned and tuned!) an Orange box ignition and dual 2.5" exhaust. HotRod did a couple that got 400HP.
Put a pair of 273 heads on your 318... Some hi octane fuel and the biggest carburetor you can find.... A set of headers. And an electric fuel pump..... Poor mans racing engine.
A guy I work with owns a black '66 Coronet convertible with the Magnum 500 wheels on it... It's been in storage for the last 20 years or so... Beautiful car!!!... He told me that it has a 318 with an auto.. But it don't look like a regular "run of the mill" 318 small block mopar... Is it possible it could be a "poly" 318 motor???? The motor in that car was never replaced...
There is a replacement for displacement. It is called RPM. A 408 pumps 408 cubes ever 2 RPMs , A 318 Pumps 408 cubes every 2.5666 RPM so it would need to turn a bit faster which it can do BTW. Also Strokers are now almost a disease. A simle increase in cubes does not garantee more in some cases less. Why? Because the cylinder heads are what limits power. When you add cubes you up the demand and often on a set of heads that can barely do the job at stock dimensions. A 408 is too big in my book. A 360 crank worked well in a 340 and I have done that (360 crank offest ground for 3.6 stroke and a 4.1 bore (060)for 380 cubes in a 340 block) That is about the practical limit. beyond that you are just moving the RPM range around not probably making anymore power unless you have some serious hi$$$$$$$$$ cylinder heads. I have done a few 318s. The later heads (pre-magnum but from a fith avenue roller cam engine) work well with 360 valves. Far better then 340 or 360 heads. Hot Rod did a 318 build . After they were done fooling around with all the "magic" stufff Arruza engines asked if they could redo it with the late 318 heads. Seems to me in street trim 355 HP. That was 40 or 50 Hp more then the 340/360 head deal. We must get over the more is always better idea and learn to match parts to the combo. That is where the real HP and torque lies. More is for over a beer but rarely translates to anything on the time ticket. Since I no longer drink I no longer am tempted. Don
my 74 duster with 318 and 3 speed manual would pull very consistant low 16s. not very fast by todays speeds but not bad. a little work and i was well into the 15s
My Buddy ran a 70 'Cuda with a 318 in the low 12's. What did he do to it...? don't know.... No spray! Tommy
This is a workhorse engine, and they can be built, but a 360 will cost the same to build, and there are lots of them around. Pistons mainly and about 9.5 to l, then a real valve job on some heads with a little porting you can do yourself with the templates from Mopar Performance. Headers of course. 300 horse easy. My son ran a 318 for years, mostly stock with headers and a 4 barrel. Won the street championship one year in stock class. Ran low 9's in the 8th, and was deadly consistent in that bracket.
I'm glad someone linked Steve Dulchich's article from Hot Rod on this deal. If memory serves correct, the casting numbers on the fifth avenue head was 302. They should be on the '85 and later roller cam 318s out in the yards. That just gives a couple of years to look for, but those cars were common as flies around here and our u-pullits are still littered with them. The real secret to those heads was the semi closed, "heart shaped" combustion chambers. It's been awhile since I built my small block Chrysler so some of this is fuzzy, but I believe that 340/360 J heads are somewhere in the 75 or 76 CC range for volume. The 302, Fifth avenue, Swirl chamber or what ever you want to call them heads had a chamber more in the range of about 53 or 54 ccs. It was quite a compression bump right there out of the gate. As they do in the article, get the valve sizes up, port the living wee out of them and they seem to work pretty damn well. I honestly considered this head back about ten years ago when I was putting the Plymouth's 360 together, but had a bit of a windfall and skipped right to a set of ported Edlebrock aluminum heads. The other way I have seen these "woke up" was to use the later Magnum heads from post '91 or so. They do bolt on to the earlier type engine, have the small combustion chamber, but a much improved exhaust port. The deal with this though is the intake manifold has to be changed to match, and the rocker train has the be changed over to hollow pushrods to oil like a small block Chev (matter of fact they used to make a kit to use Chevy based roller rockers on these conversions, Huges I believe) and if you cam has never been changed you need a lifter that has an oiling hole on top that interfaces with the hollow pushrod. Just more ideas.
<HR style="COLOR: #e5e5e5; BACKGROUND-COLOR: #e5e5e5" SIZE=1> <!-- / icon and title --><!-- message --> RPM is in no way a replacement for cubic inches. <HR style="COLOR: #e5e5e5; BACKGROUND-COLOR: #e5e5e5" SIZE=1> <!-- / icon and title --><!-- message -->RPM is in no way a replacement for cubic inches. Think what you want. That is your choice. It is however a perfect replacement. Don
My daily driver Lexus LS460L has a naturally aspirated 267 (or so) cube engine that will push its 4000lbs + size to a governed 150MPH. Something is going on under the hood, and it ain't cubes. The 318 was overshadowed by the 340, rightfully so, but then it's still biggger than a 302 Ford or a 283 Chevy and you can find tons of guys who will tell you how they had one of those engines that would chirp the tires in all 4 gears. A 318 will respond to hop-ups as well as any engine. I'm in some ways astounded that even in 2013 there are still guys who think a 383 Magnum has 440 heads on it. That myth has been floating around for over 40 years. It must be handed down like Indian folklore. Let's pick 1969...a 383 2 barrel has the exact same heads as a 440 Six Pak.
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