Hello everyone, I am planning out a 318 build. I am going around and around on the heads though. All I know, is that I want to find a set that use the LA style rocker shafts.

I have looked at the Edelbrock RPMs, but some threads seem to indicate that those aren't good for torque.

I have looked looked into the Promaxx heads. There just isn't much info out there because I think they are a new development. Do y'all know if these are reliable?

I've heard some good things about Sidewinders, but there does not seem to be much info out there for my application.

Trick-flow heads are a little pricey for what I want to do.

There is some good info on Mopar Commando W2 heads, but I have read that you need to spend about a grand at the shop to get them to perform well at all.

My favorite are currently the Indy LA-X heads. They seem affordable, and can be customized with varying levels of machine work straight from the factory. However, I think I saw somewhere that they need special 1 7/8 OD headers. Is this true? I prefer to spend less than $600.00 on headers. My truck is 4WD, so header choices are limited anyway.

My truck is heavy with the 4WD and long bed. It has the four speed manual tranny. I'm not sure what the rear end gear size is; but it rolls at about 3000 rpms at 75 MPH. Right now it has 31 inch tires (I might put 33s on it in the future) so torque is one of my big goals. Right now I am getting 11 mpg. If I could get close to 14 or better, I would be happy. Also, shooting for over 300 hp. 330 would make me happy and 350 would = really happy. That being said, streetable torque and at least 13 mpg are my top priorities.

So far I am looking to use my stock crank, KB 167 flat top pistons, Scat I beam rods, COMP Pro Magnum roller rockers, Summit 6901 camshaft and an Edelbrock Air Gap intake manifold. Any of those items could change, but so far my research (this is my first build) has shown that those components would equal a decent combination.

What do y'all think? What do you suggest on the cylinder heads for my application. I am pretty set on using my 318 block and an LA style rocker shaft style set of heads with a flat tappet cam. Besides that though, I am open to suggestions. Like I say, this is my first build, so I really don't know what I am doing. I appreciate any responses, feedback and criticisms in advance. Thank You!!!

I used a set of the Indy LA-X heads, on my 69 cuda, 410 with a procharger. It has 9 to 1 dish pistons with a mild .500 lift cam, 220 duration, it idles at 700 rpm. I dynoed it with a 750 carb and a single plane intake, without the super charger to break it in. It made 389HP don't remember the torque. I forget what the heads flowed, but they are good heads. The only thing from my experience is if you buy them, have bronze inserts installed in the heads before you use them. Mine stuck a valve, I got lucky as it did not destroy the engine. but I hear they have an issue with the stock cast iron guides and sticking valves. I really think the cooling in the heads have an issue, why they stick valves. I drove mine easy for a while while dialing in the electronic injection, and procharger. Mine stuck a valve at idle after making about a 1 mile WOT run, idling in a driveway waiting for traffic so I could drive back to the shop. I install bronze guides and all is well 3 years later.

the Promaxx heads have nice finish work.
you should not need special headers with the Indy LA-X heads, do they still make those heads though?

if yr MPH and RPM's are correct, and maybe your tire is more like 30.5", seems you have a 3.55 gear ratio.

I have a W200 with 318/auto, 34" tires, full time 4X4, it's best cruising 55-60mph because 4.10 gear ratio. Straight highway driving it's around 13-14mpg.
stock 318 motor but added headers, dual exhaust, weiand dual plane intake, holley 650, stock distributor with an MSD box.

spend some time thinking about the cam if you want good mileage, around 215* @ .050" for duration and 112-114 LSA is probably what you want.

Wow... I'll keep that in mind about the bronze guides.

How extensive was the port/polish work (if any) on the heads before the 389 hp pull?

Thanks!!!

Indy does still make the cast iron heads.

Here is the specs by Summit. Does this look good for fuel economy?

Basic Operating RPM Range:1,800-5,500
Intake Duration at 050 inch Lift:218
Exhaust Duration at 050 inch Lift:228
Duration at 050 inch Lift:218 int./228 exh.
Advertised Intake Duration:276
Advertised Exhaust Duration:288
Advertised Duration:276 int./288 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.441 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.441 in.
Valve Lift with Factory Rocker Arm Ratio:0.441 int./0.441 exh.
Lobe Separation (degrees):114
Computer-Controlled Compatible:No
Valve Springs Required:Yes
Camshaft Manufacturers Description:Fair-smooth idle, low-midrange power. Works with stock-2,000 stall, 9:1 and higher compression, and gearing.

Thanks for the responses!!!

That's a big cam for a 318 in my opinion. Especially for torque and fuel economy. I would go no bigger than 206 .050. Heads, I would use freshened up 360. just my 2 cents. Those kb pistons are 0 deck or pretty close as I recall. which is good with the bigger chamber.

T Backroader, there are a few good ways to do this with your base package 318. Your truck is HEAVY!!! Not Phat but Big Boned. So stay away from any race cam's and BIG port heads. Many times MORE is NOT better. Yes a 300+ degree 'Cheater Cam' sound real nice but your power will be way out of your needs and gas milage will suck. But it sounds so nice.

First step I'd do is maybe your stock 318 heads, just do a good valve job and light pocket porting and gasket match. On the valve job, have then do a 70 degree final bowl cut and then hand port that to blend the pocket.

A good starting point is a set of late model non Magnum 360 heads all done like I said above. These will flow more than enough for your heavy truck.

A set of Eldy NHRA non Magnum heads will also be a good start to build off of. They have a bit smaller intake port volume (176cc I think) so the torque is not moved up too high in the RPM range. They have bronze guides and the valves are 2.02/1.60. All stock hardware fits. You will need to use a 5/8" sparkplug.

Oiling.... You can do the Herb McCandless oil passage mod to increase oil flow to the main bearings. This not only improves the flow but frees up a few horsepower due to the oil pump not working so hard.
Drill 4 more 3/8" holes in your oil filter plate. Run a standard volume oil pump but if it will fit your chassis and drivetrain, install a 8 quart Kevko rear sump oil pan but only run 6 quarts of oil in it and cut the dipstick outer tube down and re mark the dipstick.

Now all that said, how many dollars are you going to spend on parts and labor??? To gain 3-4 MPG? How far would that $$$ go towards the extra gas used at 11 MPG? Where is the cross over point of pay back? Your stock 318 should run on Regular grade gas, these mods will require Preumumn grade so ANY MPG gain will be eaten up buy the extra $0.40 per gallon costs.

All these mods to a 0.030 over 318 will put out just a bit more power than a stock 5.9 Magnum with a good tune. But do a few bolt ons to that 5.9 Mag and now you really gain power for your heavy truck. Stroke is the win here for a heavy vehicle.

I was gonna say just put a 4.00 crank in it to start with.. they are cheap.. that alone will make torque
then if you wanted start thinking heads

Yep, a 390 cube kit run about $1400 to $1900 and come with 4 inch crank, Con rods, 318 0.030 over dished pistons. With a 68cc head you have 9.1:1 Compression ratio.
With a 0.060 over bore its a 396 and 9.2:1

A 4 inch arm in a 318 with mild cam and cleaned up iron heads will move a truck better than a hearty built 318 with big cam and aluminum heads.

Thanks for the responses y'all.

So do you think that I would better off going with a smaller combustion chamber (like the 302) and dished pistons, or do the flat tops with a bigger chamber?

Also, Indy offers a head ($995 a pair) that has a 1.92 intake valve and 1.625 exhaust instead of the 2.02. Would the smaller intake valve on this head be as good for my set up as the Eddy? I have heard that cast iron is easier to get compression out of, not sure if that is a wives tale or not.

I appreciate the info!!!

This is interesting.

It's only money. I love spending other peoples money.

I don't have a "Desk Top Dyno" program or I'd run a compo build of the two engines.

In the past I have done a few 318's using 302 heads pocket ported and a real good 3 angle valve job, high flow 1.92 and 1.62 valves and a 3.58" 360 crank with the mains cut down for a 349 cube mighty mini. That combo was real good but the cranks are the weak spot. You can now get that size crank in the 273/318/340 main bearing size.

What's the truck used for ? Low-RPM driving, trails, etc, or something where you're spinning it ?
I agree with the stroker & whatever CR your preferred fuel wants, for bottom- & mid-range torque.
For something that mostly lives idle-3000, smaller valves & ports & cam will generally be more responsive & efficient.
If you need heads, I'd look at a more modern chamber; the heart-shaped chambers are more efficient than the old style big chambers.
Aluminum heads will allow a bit more CR if that ends up being dictated by piston choice; stock iron heads with old-style chambers seem to have a street limit of about 9-9.5:1 for 91 octane depending on other choices.
The wallet figures into all of this as well !

You can probably find a running Gen 3 Hemi truck for $2500. Use the engine, transmission (optional) and every single wire that attaches to it. You will hit your 350hp number and can sell what's left of the truck for $500.

You can also go 360 Magnum route. I usually see good running complete engines on Craigslist for $400. 245hp/340tq will be like night and day compared to your 170hp 318.

I guess what I am trying to say is hot rodding a 318 in a truck is a waste of money and time with little gain. It's doable, but, only if you have everything given to you for free and lots of free time to do it.

if its low budget an la 360 is a great combo for towing I have one in my 1988 with the "405" speed pro pistons and a 206 at 50 comp cam and "308" heads It has 3.23 gears and has been hauling boats and cars (and firewood) great for 20 years.

The flat top kb with the indy heads sounds good too. If staying 318. I had a 1979 with a 318, and hauled everything I threw at it too, aluminum intake and small holley were the only mods to that one. Depends on the budget and expectations.

yeah, the ^ pretty much the same as the 318 in my w200. a '77.
don't really hook trailers up to it but i do haul loads of rock and dirt. it does fine with 2500lbs in the bed. 4.10 gears and 34" tires.

A 4” crankshaft is only $150 more than grinding a old one. Then you could also have good compression no matter what head you use.
I put 273 closed chamber heads on a 318 once for more compression along with a stock 340 cam. That was a really great engine for years of hard abuse.

I agree.. the stock 340 cam worked well specially on a small chamber

So, what I am saying is for a basic street and short hualing 4X4 truck, big buck Aluminum heads are overkill and not needed when there are some good IRON ones out there. Yes the aluminum heads will drop your 4X4's weight down some...... but for nothing.
In a light A or B body the weight savings would be noticed but in a 5,000 pound Aero Brickwall.....

My first engine build for my 65 B-Cuda when I yanked the 383 out of it was a 78 Lebaron 318. Bored 0.040" and 9.2:1 pistons but with the closed chamber heads it was higher compression. I did a 340 hyd cam and the ported 273 heads with a set of 1.88in and 1.60 ex valves. A Performer 318 and a 625 AFB. It was faster than the 383 4bbl.
With 2.76 SG and 253/70 14's I would drive from Auburn WA to Yakima Firing Center base and get 25 MPG. Then I put a set of 3.55:1 SG in and WOW!!!

So if that can be found, a set of 302's or 308's with 1.92 and 1.62 valves pocket ported and gasket matched on a 318 will give a big bang for the buck. On a Stroker crank, even bigger bang for the buck but you would now be at the flow limits. But I would not pass up a set of cheap stock 360 heads for this combo...

This 4X4 will never be a 7 second 8th miler or a 12 second 1/4. So IMHO, don't spend money trying to make it one.

So, I didn't really consider the octane issue. What compression level do y'all think I would start needing to use the higher oct? Does hardened valve seats allow the compression to go higher (like on the 302)? I do prefer to burn low octane, not just for price, but because the ethanol is so bad for the fuel systems. I have replaced the 2bl carb 3 times since I got the truck in 09. And that is with a can of B12 poured into the tank ever other month. I hate ethanol, I'm literally writing a thesis on why I do for a class right now.

I'm kinda up in the air between doing 302/8 heads on my 318 or dropping a 5.9 like y'all said. I could keep my 318 for a light Duster or something someday later. After pricing 5.9s on FB marketplace, there's like 3 of them within 200 miles from me for 400 bucks. Would my fuel economy go down with the bigger Magnum? If I hopped it up a little, or decided to put a carb on a Magnum, would I run into the same octane/detonation problem?

I really appreciate y'all's input. You have saved me from putting together a motor for the wrong application.