We're building a 1970 Dodge stepside truck with our 21 year old daughter. We don't have much experience with Dodge builds. The 318 block is ready to go, but I am questioning what cam and heads I should use. I have the original stock heads that need to be rebuilt. If we want to have a nice street rod that doesn't guzzle gas and still sounds healthy, should we go with a different head? And what cam set-up what be suggested? Have an Edelbrock "Street-Master" intake manifold and plan on using a Holley 650cfm "econo-master" four barrel carb. Casting numbers on the head we have is 2843675-16. We also have another set of heads with casting numbers 4027593 that are later model. Since my builder wants $400 to do a valve job and replace seats and guides, would we be better off to get a set of heads that are rebuilt from E-bay? Thanks... MeanJean
Thank you for doing an intro before posting so many people have a problem with that. As far as heads go for the 318, if you can find them get some swirl port heads from an early 90's pre-magnum motor. They work great for mild motors. As far as a cam goes, I would try something with in the .450 lift range. My first car had a 318 with that intake and it reponded pretty well with just a mild cam.
yeah I am buildin a 318 too right now for my mud truck. I got a 77 318,the motor thats in the truck and a balanced marine 318 that runs but smokes a little upon start up. I dunno what heads are on either of the motors I got. I havent gotten that far. BUT I was curious on what cam/intake an carb also. Does anyone see any prob with me goin with a RV cam, holly duelplane intake and either a quadrajet or a eldelbrock 600??
Hey Spudz I am unloading all my Mopar stuff, since you are so close let me know if ya need anything. As far as the intake any dual plane should work fine. I would stick with a Edelbrock or Holley carb though.
A while back i helped a friend build a 318 for his ramcharger. we used a mopar performance stock 340 cam and it worked great.Although i am not a big fan of quadrajunks,4-wheelin is one place thay work pretty good. those small primarys allow for good low end torque.what ever you do ,don't use 360 heads.there ports are to big and will totaly kill low end torque.
Do an archive search on Hot Rod's website. They had a killer article a couple years back on squeezing 400 hp for $1,500 out of a 318. They stated that the biggest problem from the factory was a lack of compression and airflow. Milling the deck a bit and thin head gaskets or domed pistons will take care of the first half, while a pretty thorough port job will take care of the other. I can dig through my stack o' mags tomorrow for the article if you'd like.
As long as we are on 318's Ive got a question. My 85 van (9/84 build date) has around 375K on the original 318 (stock 2bbl) and it smokes a lot on startup and at idle. Compression is 135-145 in all cylinders so Im suspecting the guides are shot. A friend has a set from a 74 motor that were redone and have about 45K on them before he lunched the block, the price is $75. Are those heads OK to use or will I lose performance? Im primarily interested in low to mid range as this is a working vehicle used for towing. Yes, I realize that is a lot of miles to be spending money on but if I can get another 50-60K before the body disappears I'll be happy!
Way too often I hear guys say you need to put 360 heads on a 318 before it will run. The 318 heads work just fine up to 5,000- 5,500 RPMs. Reality is that is way more then most 318s ever see on the street. Seems most Hot Rod Mopar build ups are concerned with drag racing improvements and offer very little noticable performance improvement on a street driven car. I had a 340 in a Road Runner I drove on the street for a few years, very big hydralic cam, 600 Holley, headers, Hemi 4 speed, 3500 lbs clutch, ****terscield, 3:23 gears with G60x15 tires, you get the idea, with 318 heads. Heads were match ported to the intake, had a good valve job, and new valve guides. Car was entirely street driven. Very quick throdle responce, flat screemed up to 4500 rpm where it ran out of air. I always power shifted it intro 2nd @4500. 318 heads worked on that, i'm pretty sure they will work just fine on your stock motor. Except for the mid 80s introduction of the roller lifters and sweral port heads, very little had changed on 318 heads. Around 73, Chrysler put in hardened valve seats, if you just redoing a set of heads for a street car, I would step up to the hardened seat heads (or have the hardened seats put in your heads.) If you do a set of heads, have the valve guides REPLACED, don't let them con you into the idea thet nuraled (sp?) guides are just as good, in a few years the nuraling will be worn out and the motor will huff a little blue (oil) smoke on start ups. If you are going to buy a set of heads, step up to the sweral port heads. Exhaust restriction is the biggest horsepower theaf on 318s, and most of that restriction was in the single exhaust. The 340 grind cam works very well in a otherwise stock 318. Spend a few bucks and buy a GOOD timing chain and gears, not the cheapest thing you can find. Put on the dual exhaust (even without headers). The factory cast iron 4bbl intakes were very good pieces, the only thing the alumium intakes did was save weight. Contrary to popular belief, the 340 intakes work fine on the smaller 318 head ports. If it really bugs you you can match the head with the 340 intake gasket (top and center of ports are the important area) but on the street that really is probably an over kill. Factory intakes could be had in square bore (standard Holley or AFB ) or spread bore (Thermoquad or Quadrajet), although the square bore intakes may take some digging to come up with. I'd stick with a square bore carb in the 600 cfm range, or you can probably get away with a spread bore carb up to 780 cfm. Either way, electric choke and va***e secondaries please. This combo will work great for a street driven car/ truck you may be looking for a little extra kick from. Now, if your going to be racing your 318, the story will be quite different... The biggest bang for your buck with small block Mopars is found in the head work. Gene
With 375 K on the heads in your van, the guides have got to be shot. (as wells as the timing chain) Bolting on any redone heads and a new timing chain will most likely improve your performance. I would check with your buddy to see if the valve guides were replaced or if they were nuraled (sp?) At 45K nuraled guides are probably almost shot. Another concern may be if you replace the heads with ones that are actually sealed, it may start pulling up a lot of oil past the worn rings, then again, might not either. Gene
The biggest thing about the 318 is getting them to breathe. Someone said the 360 heads won't help - I beg to differ. I put them on the 318 in my Z car & it's torquey as hell, & I still have the stock cam. Go with the 360 big-valve heads, & get a cam designed for the RPM range you plan to run in. Mopar makes their "Purple" cam shafts or go with one of several other manufacturers; they all make good mid-range cams. You have the intake & carb. so I won't go into that (but the old Carter Themoquads are bulletproof - even with the plastic center). Dual exhaust & you're good to go. ~ Paul aka "Tha Driver" Easy on the Giggle Cream!
OK, I'll bite, what's a z car??? And what motor was in the "z car" before? I'll also bet you put the dual exhaust on when you put the 360 heads on? Gene
Sorry; '77 Datsun 280 Z (stock is straight 6). I don't have the dual exhaust yet as it's a work in progress. I plan to install a 450-500HP 340 with fenderwell headers if I don't find a streetrod body to put it in. If I do, then I'll add a cam (which I have used) & the dual exhaust to the 318. Without the cam, it won't wind up; but it sure has the torque! http://AngelOnEarth.net/ZCar/ZCar.html ~ Paul aka "Tha Driver" Easy on the Giggle Cream!
I've found that the 340 heads are too much for a 318 street or race (2.02 1.60 valves), but imo the 360 heads (1.88 1.60 valves) aren't too much for the street. for a truck, I'd recommend a four barrel carb from 500 to 600 cfm. If it were me I'd want a 360 2bbl intake with a 500 cfm holley 2bbl. The 340 cams in the 318's work great. I think the 360 exhaust manifolds flow pretty well too on a 318, and you wouldn't need to be forever tightning header bolts on a daily driven truck. The mopar performance book says that the new magnum exh manifolds 92-01 flow almost as good as the 340 exhaust manifolds. If you're going to have the stock heads rebuilt, at least gasket match the ports and do a little bowl work. Flow, compression, and cam are the 3 major shortcomings of the 318.
Dude, i'll bet your "z" is under 2800 pounds. thats at least 1200 pounds less than tomanjean '70 or spuds '77 4x4. In your ride the 360 heads work good becose your car is light enough to not notice or miss that lost torque.plus you can make more hp in the high rpm's,but in a heavy truck you nead all the torque you can make. I can tell you first hand mild 318s with 360 heads in a big dodge truck aint no good.If I can find it i have an old mopar action 318 build up and dyno test article. 318+.030 ,a 340 purple shaft, 9.0:1 MP pistons,stock rebuilt318 heads,performer intake and a 600 holley. 360 heads rebuilt and milled for more compression were added after a dyno pull and showed a loss of torque and horsepower. P.S. On a different note,ever take that thing to the track?I'm wondering what it runs in the quarter.
The $400 seems like an ok price for a good rebuild. Unless you can find a $200 set of heads on Ebay that you can inspect before bidding on, I'd say to build one of the sets you have. 50Dodge4x4 has good advice on the guides (and pretty much everything else he said)- NO KNURLING! Get 'em replaced for that $400. All my Mopar engine books are at home--if nobody runs those casting numbers for you by tonight, I'll let you know what they are. Whichever set can get you in the low-to-mid 9's for compression ratio is probably your best bet. I run a cam with .420 lift, 203 degrees duration in a 4300 lb car, and it runs low 17's in the 1/4 mile on 2.93 gears. Not a race car, but decent for a little 318 in that combo, and it idles like stock. You could run a little more aggressive cam and have a more rugged sound without sacrificing driveability. A 650 carb is a good match- I happen to run a 600 Edelbrock on mine, and with those cruiser gears, I get 15 mpg or better on the highway.
The heads you want are from the late 80's. The casting number ends with 302. Look in 85 Diplomats and the like. These are swirlport heads with heart shaped valves. Have the block side milled some to increase compression and have the intake side milled so you don't have to have the intake itself milled. As with any head, have them checked for cracks first. The 340 grind in a good one too. As for exhaust, get manifolds for a magnum engine. They flow better that 70 manifold. Another option is running a magnum 318 head. Those are the tops, but those head use a different intake. You can redrill the heads to take a LA intake or buy a Magnum or magnum/LA intake. The problem with the 340 or LA360 head is that they interduce more air/fuel to the engine than can flow out.
On my car, it's just something I'm peicing together out of spare parts. Well except for the fibergl*** peices which I bought back when I had a little money - & got carried away. LOL! I doubt it would be very quick in the 1/4 'cause it runs out of revs very quickly with the stock cam. I'll get to that one day... As for the OP's truck, I was ***uming a stock compression 318 (I don't think he said anything about high-compression pistons), & I believe just swapping to the 360 big-valve heads will make a large difference in both torque & power - especially with a dual plane manifold & 4bbl. The difference is in the valves - not the heads themselves. It's just cheaper to pick up a nice set of used 360 heads than to have big valves put in a 318 head. Thus the reason for my suggestion. If the owner wants to build a perfect engine, he needs to start doing the math to match cubic inches, compression, valve size, cam, intake, & carb. Speaking of which; does anybody have the formula for that? It's been years since I've done it & I have no idea where I've stashed it or even if I still have it. I need it to build the 340.... ~ Paul aka "Tha Driver" Giggle Cream - it makes dessert *funny*!
back in the day ....( around 92 or so....) i had a 340 i built for a 63 valiant pro street car......10 1/2 to 1 ....60 over.....and monster pair of x heads....that were ported to the max.....with a 500 plus solid cam ....tm intake....and a 750 holley ....you get the picture ....good to 7500 no problem .....usuable.....well not really .....had a 4 speed with 410 gears....which would have been good if it had say a 28" tall tire.....but this was the early 90's....back when pro street ruled the roost......this pup had 21.5x33's.....so as you can imagine....it was a little doggie out of the hole.....so i did a total engine make over.....left the short block ....but went to a comp cams 268 hi energy mild hyd.....left the edelbrock tm intake....(in hind sight i probably would have use a dual plane......) and a pair of small valve j heads.... ran a 750 vacuum secondary holley (which was waaaaay too big...should have run a 600 or so ....) had a cheap dayco "hemi" convertor behind it.......made a nice difference .....also had a 360 little red wagon cam in a 273 that made a real runner out of it...but a lot has changed since then ....and a lot of better stuff has come out.....and become more avalible......like the magnum heads....and the edelbrock heads....brandon
593 heads have a 63 cc nominal combustion chamber volume, and the 675's have 60 cc chambers, so of the heads you have, I'd stick with the stock 60 cc ones to keep the compression ratio up.
BRANDON.nice ride.you are dead right on the gear. I have a 66 valiant that runs low twelves on 4:10 gear with a28x9x15 slicks.this is a street car that i drive to the track,whith a 360 and an 833 four speed.it is a little soft out of the hole and would run faster with a 4.30 but i dont have a trailor to tow the car on.nice to see another valiant owner on here.if i get a chance ill post pics soon.it might not be traditional but its still cool. As far as the 318 build up, i think most every one is just saying not to get carried away and build something you cant drive.go mild now,and upgrade later if neaded.the most populare mistakes in hot roding is to go overboard.bigger is not always better! P.S. if im not mistaken that little red express cam is the same as the stock 340 cam.still a good cam for a 318.
Thanks for all your input! The 675's are 60cc heads? That is very good to know I looked up the head spec's, but didn't find the chamber sizes in my search. I am torn between paying to have the original heads worked or bidding on a set of 593's on e-bay. And I am definitely looking at the Comp Cam XE268, so thanks for backing me up on that. We don't want a strip racer...just a fun, dependable, and healthy sounding ride! We're glad that we found this forum...You guy's are very helpful Is anybody familiar with the Edelbrock "StreetMaster" intake? Is that a good choice...since it is already hanging around in the shop? MeanJean
You'll have better throttle response with an Edelbrock Performer and the stock heads redone. For the heads just clean up the bowl behind the valves and match the ports to the gaskets. Keep it simple. back cut valves. The comp cam is good but Melling makes one with similar specs for much less money. spend on the double roller timing set and a good set of headers. We will be using later model 92-96 Dakota headers (Doug Thorley Tri-Y ceramic coated) in our 40 ch***is. We have gotten all of our speed parts used off Ebay for about half retail.
I have done dozens of mopars...just do the following for a nice daily driver. Take the 675 heads you have and get them rebuilt with a good valve job and 340 valve springs. Stab in a 340 timing chain, camshaft, a set of 1 5/8" headers, and a good dual plane intake. I personally like the 68-72' 340 Intakes. I believe the old streetmasters were a single planes. If so it will kill botten end torque. The streetmaser IIRC was a small port intake that matches the small port 318 heads. A 600cfm carb is a good choice for a square bore, or a 72'-74 thermoquad if spread bore. I would go with the Edelbrock or Carter abf style carb if you are going aftermarket however and lean it out some as it will be a little rich. Setup the thermoquad exactly the same as a 72' 340 and you are set.
So, are the 675's are definitely the 60 cc and the 593's are 63 cc? Just asking for double verification... And what kind of a difference are we talking with the "StreetMaster" single plane vs. "Performer" dual plane intake? Is it pennies or are we talking nickles and dimes? I understand a dual plane design being more efficient...but is it a drastic difference? It's not that we don't want to do it right...just gotta take those dollar bills into consideration! Thinkin' the dollars would be better spent on the exhaust system ... Maybe we'll have to change the intake later down the road. MeanJean My Daddy always said "You can't **** it if you can't blow it"...
Hey! Hope that everyone had an awesome Father's Day! We took the family and my pride and joy (1954 Ariel Square Four) to a Vintage Bike show in Ventura. Brought home a second place trophy Now we are back to the 318... Bought a set of 593 heads ready to bolt 'n go for $100 They are slightly different than stock, but after we plugged up the smog holes on the exhuast sides we look good to go! We just tapped and bolted the little holes in the heads. Now we are looking at these big holes just above the exhaust ports that warm up the intake manifold...they look like extra ports that don't go anywhere, and the intake manifold doesn't cover them...( same as on the stock heads btw) I don't understand All I can guess is that there is something that bolts on top of the intake on both sides that covers it...( but what?...) Like I said before, we haven't played with Mopar...mostly Chevy Anybody know what I'm talking about? MeanJean
are you talking about the upside down "U" shaped holes? I saw that too on my 360 and wondered. I believe that is some requirement of the casting process because my intake doesn't cover them either. And the motor is running great for me.
Don't worry about those U holes. Only the little ones in the center flow exhaust. The 340 intakes are $50 around here. Performers are usually $75 and actually are not as good. The Performer RPM is a very good intake but looks just like the early 340 intake but aluminum! The old LD340 is also a very good intake. The Airgap RPM is about the best dual plane for the small mopar right now. Stay away from the Offy 360 degree intake on a 318 - way too much plenum volume.
Performer is a 273/318 intake RPM is a 340/360 intake as is the LD340 The LD40 is a 273/318 intake. If you use a 340 or 360 style intake on a 318 head it wont flow well. You can go small port(intake) to large port(head) but not the other way around. One other thing, the Performer series is the only after market intake that will work with A/C.
Wow, I have been looking for info on getting more power from my 318 for weeks. This is the most helpful topic I have found!!! Seems on all the mopar sites I find they hate the 318.
I've got a mild 318 that I built a couple years ago. It's a factory police interceptor. All that means is that it had 360 heads and intake, double roller timing chain, and a windage tray. The single greatest improvement you can make on these engines is to increase the compression. Mopar adjusted their compression ratio by changing the pin to crown height on the pistons. (Unlike Chevrolet, that played around with combustion chamber volume.) Don't forget about the 318 Poly pistons. They have a taller pin to crown height than the LA series 318. Find a set of '85 and up 318 heads, order an Edelbrock Rpm Air Gap intake, whatever carb you like best, and a Crane Cams Extreme Energy 268H cam. Then get a set of headers with 1 5/8" primary tubes and 2 1/2" collectors. Use the early 70's Mopar electronic ignition, and you'll be all set with a strong mild street engine.
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