318 LA build

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needsaresto said:
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Then again theres the eq magnums as well.


Your opinion has been noted,lol.

There are some here who do not like the magnum.

I for one cant argue with cheap chev price roller rockers,and a boost to 9:1! They make great street heads and the nice thing is they'll make 400h.p on your 318 with no porting.Magnums also produce a very flat and fat torque curve

All heads crack eventually. Id run em without fear myself. I still have my pair here and a 360 waiting for them. Some good porting on the magnums and I think 450 hp is not hard to achieve.
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Thats because people like me and Justin don't see the great gain in losing valvetrain reliability, running heads that are FAMOUS for cracking, just to gain mythical power we both have achieved and beyond with old style heads and a bit of tuning.

All heads don't crack in 30K miles, not like mine havent been cracked for 200K in my 95, just sayin'..........


Want a set of EXCELLENT street heads, that BOLT ON a 318??????


302


Just the opinion of a 318 guy..........
 
Here is my low buck 318 combo in my dart. Most guys are shocked that it's a little 318.

.040 rebuild with flat tops pistons,
Junk yard magnums with valve job, chevy beehive springs and retainers
1.6 chevy roller rockers
Comp XE256
Crosswind intake
Holley 600 4160
Hooker headers
3,000 stall converter
3.91 gears

The car is a blast and is a tire smoker with skinny street tires.
 

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what did you need to do in order to use chevy rockers and springs on the magnum heads?
 
caferacerx said:
what did you need to do in order to use chevy rockers and springs on the magnum heads?
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Springs and rockers were both a bolt on deal with no machining. There is a thread over on moparts about using the springs. They are just a good cheap replacment for the stock springs and can be bought over the counter at any chevy dealership.

To use the rockers I had to go to hardened pushrods and use Comp Cams guide plates. Great cheap setup and the valve geometry is spot on. I have 4,000 hard miles with no issues.
 
The spring you want is the gm 3100 valve spring.

It's funny how lots of guys will say they will never go with the magnum because it has a chev style valve train thats weak. Lol its just fine for 6000 rpm or so. The weak point of chevs valvetrain always seemed to be the cheap *** stamped rockers. Pushrods will punch a hole thru the cup area.

As for the magnums cracking,I dont really fear that either.Yes they crack but I think it's kind of an urban legend thing thats blown waaay out of proportion.
 
needsaresto said:
As for the magnums cracking,I dont really fear that either.Yes they crack but I think it's kind of an urban legend thing thats blown waaay out of proportion.
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I feel the same way. I pulled mine myself from a Jeep Grand Cherokee with 150K and had no cracks.
 
Badart said:
I feel the same way. I pulled mine myself from a Jeep Grand Cherokee with 150K and had no cracks.
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They will crack and run......till it's gets into the exhaust valve seat, then you begin to 'notice' the problem.

No urban legend, seriously.

they will/can crack at the edge of the chamber, between valves,the valve seat itself.



Technically, I've seen old small block iron crack in the meat around the spark plug [chamber side], but this crack does nothing, go's no further than that in every case I've seen, mine x heads did this=I ground'em down and have had them on 2 engines with no issue or further cracking.

I've also seen 1 set of j heads that were on a work truck that was HEAVILY abused/overheated-blown gaskets, thing in this instance is also that there was a dark area in the casting where they cracked which os a text book sign of sand pooling in the cast =casting flaw these heads actually cracked on the flats either side of the 2 center exhaust ports...flange side, very weird.


However....mag heads have cracked everywhere around the chamber/valves in my experience...and many instances too.

Even the 302 cracks [exhaust valve into the closed chamber area, right at the peak/heart' ] easier than the 675 318 heads, but not nearly as often as mag'em heads-hence the nick name mag'em/cracknums etc....
 
I'm not sure what the actual difference in such a mild motor would be between the 675 head and the magnum. I don't think much. BUt from the OP, ,it seems he was looking for a cheap and easy way to gain a bit of power while waiting for the future.........

Not looking for some chevy ****, and crackem heads...........

I could be wrong.
 
For a mild build stock heads are fine you can add 100 HP to a 318 without changing the heads and will probably see MPG increase as well. You can get your 318 to stock 340 HP levels using those 318 heads which should be a pretty decent runner.
 
I am just saying that my experience has been good and I have something unique. My mopar, chevy and ford parts all work together in harmony. LOL.
 
Solracmopar, I told you that you would get all kinds of opinions! Getting back to your original post it sounded to ME like you wanted to do what you could with your available parts, minimal cash outlay and ultimate goal of building a performance 360 when the rest of the car was complete. To that end I would concentrate on parts that will enhance the performance of your 318 and will work equally well with your 360. My suggestion: headers & exhaust system, converter, rear gear ratio. Without higher compression through pistons or small camber heads your just plain limited in what you can do without spending a fair amount of money on the motor. Keep your stock heads and look for a good 318 specific intake and cam which will work with those upgrades and will also be selling points when the time comes to off load the 318. Now, guys, lets give the kid some suggestions on affordable intake, cam, header, converter and gear combos!
 
solracmopar said:
Thanks for all the input. My original plan was to run a set of late model Magnum heads, Edy RPM intake, 650cfm carb, 218/228 cam and doing the longer push rods etc Magnum set up..

Rublefish I appreciate your accurate numbers and think thats the route I'm going to take for now. Basically a mild 318 but more than the bone stock set up I'm running now.

Later down the road when the entire car is back together and I start driving it.. I might pick up a late model 360 and build that as a proper performance engine. Just want to add that this is an AWESOME site with people who actually care about Mopar.
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your plan sounds like the best plan, it appears you know what you want and how to achieve it, dont second guess your self you are on the right track
 
All heads crack eventually? Where'd that bench racin crap come from? Just not true. Heads crack for a reason. They don't "just crack" eventually. I would run the crappiest flowing LA head any day of the week over the best flowing magnum head. Having worked in a machine shop for a while, I had the chance to do some interesting things. Such as put a dial indicator on rocker bolts and studs of various engines. You can see some serious flex when you do that. I've seen small chevy studs flex as much as in the .070" range. Also, it's a complete myth that the 302 needs porting on a 318. It's just not so for anything but the most radical of builds. Want compression and a "chevy" style rocker arm? Then my recommendation to you would be to build a small block chevy with some 186 heads and go join a chevy forum. chevys are good engines. I happen to like them. but there's a reason Mopars are better and stronger out of the box, with all parts equal. Notice I didn't say anything about budget being equal. PARTS. Stock for stock the Mopar beats the HOUND out of the chevy every single time. You can see the difference in the tear down and in the build. the design differences are light years apart. the cylinder head department has always belonged to mopar. as I've said before, I've had the pleasure of having access to the dyno and flow bench room at Mercer University in Macon on many occasions. I've seen the differences between the chevy BOW TIE and the Chrysler X and J heads and the Chryslers came out on top. use the magnum heads. a lot of people do. a lot of people get out run by 40 year old cylinder head technology everyday, too.
 
These days they all crack.lighter heads mean less meat in the casting,leaner fuel mix means hotter chamber temps etc. The vortex heads crack too because of the casting tecnollogy etc.

Any ways,I have a set of mags.I'll run em .Done.And no I dont "want" a chev style head. But who in thier right mind would not use a good quality chev small block rocker that costs waaay less on thier magnum? I guess guys who think spending more will win races,lol

Oh just for the record the magnums arent chev style heads.Thier actually based on the old AMC design,lol
 
No doubt I am going to run the stock LA heads. Question is what kind of springs do I run with a 218/228 cam?
 
How much valve lift will you have with that cam? I would think for moderate lift the 340 Stock replacements would serve well.
 
StrokerScamp said:
Want compression and a "chevy" style rocker arm? Then my recommendation to you would be to build a small block chevy with some 186 heads and go join a chevy forum. QUOTE]

WTH? It's a mopar head. BTW I thought you said that you were quitting and leaving last week? Let's just all do it your way, because any other way won't work and that makes it junk.

I'm also running a Ford 9" under my dart too. Should I join a blue oval forum too?
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UNless you are completely sold on the 218/228 cam..........

Keep the intake and exaust duration the same, I gurantee if you ran them both, the same day, you would be more happy with a same/same cam, near the same duration.

Coming from dozens of stock engine experience 318 wise in trucks, motorhomes, cars, etc. Just because it is "designed" for manifolds, or different percentages on the ent/ex flow, etc, and makes results on the dyno, doesn't mean it is the best actually in the car in every day use.

Not to mention, from my experience, the 268/276 340 cam, gets about 1MPG less than the 268/268 comp, in the SAME engine, truck, just a cam swap day apart. (When I was younger I couldn't leave a cam alone longer than it too to afford another one) The 268 high energy was a "hotter" cam too, and it still made more torque than the 340 cam.

If it was me, and I was in your shoes, even though I HATE comp lately, I would spring for the tried and true 260/260, runs like stock, with more power, idle-5K.

Case in point, I had a performer, 600 edel, headers, and a 260/260 comp in my dually a few years back. Heads had NEVER been off the engine, and, with 4.88's, it ran the 1/4 at like 14.96, or 14.91, at like 86MPH I think, it's been a while. Prety good for a one ton dually truck, with a 318.

Just my op onion...... :)
 
StrokerScamp said:
All heads crack eventually? Where'd that bench racin crap come from? Just not true. Heads crack for a reason. They don't "just crack" eventually. I would run the crappiest flowing LA head any day of the week over the best flowing magnum head. Having worked in a machine shop for a while, I had the chance to do some interesting things. Such as put a dial indicator on rocker bolts and studs of various engines. You can see some serious flex when you do that. I've seen small chevy studs flex as much as in the .070" range. Also, it's a complete myth that the 302 needs porting on a 318. It's just not so for anything but the most radical of builds. Want compression and a "chevy" style rocker arm? Then my recommendation to you would be to build a small block chevy with some 186 heads and go join a chevy forum. chevys are good engines. I happen to like them. but there's a reason Mopars are better and stronger out of the box, with all parts equal. Notice I didn't say anything about budget being equal. PARTS. Stock for stock the Mopar beats the HOUND out of the chevy every single time. You can see the difference in the tear down and in the build. the design differences are light years apart. the cylinder head department has always belonged to mopar. as I've said before, I've had the pleasure of having access to the dyno and flow bench room at Mercer University in Macon on many occasions. I've seen the differences between the chevy BOW TIE and the Chrysler X and J heads and the Chryslers came out on top. use the magnum heads. a lot of people do. a lot of people get out run by 40 year old cylinder head technology everyday, too.
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Someone needs a prescription for some medical marijoowanna!!!!!!
 
My 318, I used stock pistons,
# 302 heads, {Rebuilt at Napa machine shop}
Edelbrock LD4B intake
{Has small ports, this intake was made for the 318, not a 340}
Mopar performance cam,P4452759AB Duration 260/268, Lift .430/.450
Edelbrock # 1406 600cfm carb electric choke.
dual exhaust off the stock manifolds.

[ame="http://www.youtube.com/watch?v=Ud8mci4rjFU"]YouTube - 1964 Valiant dual exhaust[/ame]
 
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