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Discussion Starter · #1 ·
Hey Guys. Been reading bunches of stuff from all sorts of sites about "building" the LA-style 318 i currently have in my 86 W140 Auto 4x4. My current goal is gain the most noticeable power for the least cost. From what i have read the must-do mods are as follows:

Stock Cast Iron Intake and Four-Barrel from a 80's 360 in the JunkYard (along with air-cleaner)
Carb Rebuild Kit for Used Carb
Set of Cheapo Used Headers
Advance Timing and Lighter Springs for the Factory Distributor

I understand the purpose of these mods and with the help of my friend who is a mechanic I'm confident we can do the above mods. However, after reading more and more these things i need a little help making these decisions below:

1) My friend says he can port heads. With this practically free skill available i obviously want to take advantage. However, do i have the #302 casting heads on my factory motor already?? I see most people swap early 318 LA heads for either the 302's or Magnums, however id like to stay away from the mags if i have a decent set of heads already.

2) If i have the #302 casting heads, what should i do with them for the best bang for the buck? Get them milled?? and/or what is the cheapest way to put in bigger valves?? i am a total newbie when it comes to automotive valve train but in researching the 318 i hear people swap the factory 302 valves for the larger 360 valves. Are they buying them used?? I know new valves from Summit would be at least $200 but its not really in my budget...

3) Larger Cam, which to buy??... I plan to eventually run a 35x14.50 tire with most likely 4.10's in the rear and would like to buy a cam only once ;) even if it isn't the most street able truck with the factory gearing and tires. Also, what is need parts wise other than the cam itself for install??

4)What should i do with the fan?? I hear talk of the viscous fan and electric fan, what would be best with my budget and goals??

Thanks in advance for the help and support guys.
 

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The stock 360 cast-iron intake is dirt cheap, and still a very effective performer, certainly viable against current aluminum models. However, the ports in it are 340/360-sized. Using it with 318 heads sets up a considerable port mis-match (we're talking LA heads here), so you defeat the purpose. Unless you plan on hogging out the 318 heads you have to the 360 size, you should use a Performer or Mopar M1. Read this article on adding 100HP with some very basic bolt-ons/bolt-ins for the 318.
http://www.moparmusclemagazine.com/...opp_0312_318_long_block_bolt_ons/viewall.html

This links to a 400hp junkyard 318 buildup where they actually do hog out the 318 heads to 360 size and install bigger valves.
http://www.hotrod.com/howto/113_0304_318_small_block_build/viewall.html

Here's another 400hp 318 build, this one using a Magnum head swap. Read all three. It'll clear up many questions. Note what cams are used and why.
http://www.moparmusclemagazine.com/techarticles/mopp_0409_318_engine_build/viewall.html

Those three articles show how simple it is to take both ends of the approach.
If by some chance you managed to get a roller-cam 318 (kind of a gray area as to when they were phased into the truck line), very similar roller cam profiles are available.

You don't want to push too much on compression. It is better to have enough compression to match your cam choice while running full ignition advance than it is to run too high CR and have to hobble the ignition advance or run max octane gas to keep the rattles away.
Back when lead was being phased out test after test showed a lower compression engine running full ignition advance consistently produced more power (under the curve - where it is useful) than higher compression engines running limited advance.
 

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Discussion Starter · #3 · (Edited)
The plan if i can figure it out is to do a fairly aggressive port to my factory 318 heads and install larger valves. This would allow me to use the cheaper cast iron 360 intake and factory 4 barrel setup, correct?

EDIT: Another question: can i get away with just porting the heads and leaving the factory valves with a mild cam?? This motor is obviously in a truck, and i really don't see it reaching high rpms very often.

However, i don't wanna spend say $100 for a used intake and 4 barrel then somehow drop $200 on just valves. Is there a cheaper way to get larger valves in my 318?
 

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At some point in the 80's they started using the 360 head son both engines (can't remember when). If you have the 360 heads, then you won't have to worry about port mismatch and you will have room to put 2.02 intake valves and bigger exhaust valves in. You can probably find a cheap Edelbrock performer aluminum dual plane used (I got one for a 360 for about $50 back in late 90's).

Possibly finding a junkyard 360 (local pick-n-pull by me has a ton of them in 90's Rams, but they're Magnums) in good shape and just buying the Magnum carb manifold might be easier and solve a whole bunch of stuff all at once. The advantages of this swap are: ease of bolt in; instant power increase due to displacement, cam and heads; everything that bolts to an LA will bolt to the Magnum, like accessories, etc. Only other major thing that would get in the way is you would need a 360 specific/externally weighted torque converter, as the 273/318/340 are internally balanced, but the 360 is external.
 

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Discussion Starter · #5 ·
The 360 magnum swap would definitely be the ideal solution. However, after 500 for the motor at a Junkyard, and at least $150 for the Magnum carb intake, and a weighted torque converter or B&M flex plate, carb, a now a fuel pump and regulator for that carb since it is no longer fuel injected i will be well over $1000 by the time I'm done.

My main goal is to piece together a strong (enough to ride around in town with maybe 36's after 4.10 gears) and reliable motor using the motor i have. According to my step dad, when my grandfather owned it he had the motor "rebuilt". Since i can't tell what that means till i open her up, I just wanna assume the pistons are good, with maybe a mild bore, and utilize them to there maximum.

In regards to that, if my heads are indeed 318 heads can i:

1) Have my buddy do a port job to match the intake size/pattern of say a cast iron 360 intake?
2) Port the exhaust to match a gasket set for say 360 headers (already have the headers for $50)
3) Clean up the 318 valves and run them with a mild/agressive cam?? If its within budget would stiffer springs help with the cam (i know I'm sorry if thats a stupid question, still new at this)

If the above answers are all yes, i figured my parts list would look something like this...

Junkyard Carb and Intake (rebuild kit as well): $100
Port Job: Case of Beer for my Buddy $15
Headers: $50
Gaskets: $35-50
Cam: $100 or so (still clueless bout this, but getting there)
Advance Timing: Free
New plugs, wires, cap: $65

All this together would be around $350, something i can definitely afford as a college kid and hopefully give me a good cruiser.
 

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You will need to do your homework during engine teardown to findout what you have before you start making decisions. First off the 360 head always has the 1.88 intake valve. There were late model 318 4bbl's offered (mostly police pkg's) these all had the 360 head and intake combo. The biggest problem no one has mentioned o you is that if you attempt to put 2.02's in a 318 the block must be notched to fit the 2.02's ..way out of your budget. When you pull your heads you may find you have 1.88 intake valves not 1.72's. at the end of the day I thnk that you can make plently of power with 1.72 valves and port matching to a 360 cast iron intake. Were talking a truck here and your looking for torque not top end horsepower. Tear her down and you will find your answer.
 

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Discussion Starter · #7 ·
I think you just made my decision for me. As you mentioned it is a truck application that will rarely see high rpms. So definitely going iron 360 intake, 4 bbl, port matched heads (regardless of valve size, just sticking with what i got), headers, true dual exhaust, and advanced timing (thinking 10 degrees before seems to be the common answer here).

Still leaves me clueless about cam choice?? I've heard everything from the Factory 340 cam to a Comp Extreme 268. I can almost guarantee the intake valves are the factory 1.72s and the pistons will be factory as well (slight possibility they may have a mild bore however). I may do thinner head gaskets but I've decided against milling them down if that matters as well.

Where does this leave me??
 

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Factory 340 cam may be a good choice.. I would shop around Summit, Jegs to see if I can find a cam for cheep.. never buy a used cam IMO. You will need cam and lifters always and if your budget allows new springs.. The famous purple shaft is the 284 and may be too much for your application with 1.72's the last 340/360 cam for the HP 340/360 with low compression will be your best bet. do not go thinner head gasket that is the LA's one down fall. Use a good quality fel-pro stock gasket. find a set of small tube headders.. fit better anyway and 2" pipe from the collector.
 

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Discussion Starter · #9 ·
sounds good guys. i appreciate all the help. when i get this project going i gonna take pictures and report back. i know i love watching other peoples' projects come together, why not share the love :smileup: I'm sure i will have some more questions along the way but so far i feel like I'm in good hands.
 

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Do not waste time port matching the heads if you're going to keep the stock 1.78/1.50 valves. This will kill port velocity and reduce volumetric efficiency (slow mixture moving past small valves). If anything, step up to 1.88/1.60 valves and leave the ports alone (fast mixture moving past larger valves). Get a Performer intake off of eBay. The 360 heads on 318 from the factory was a limited production run called the E48 package, mostly used in cop cars, though I do have an RC with it, and have seen it on a couple 80's vans. You could do the same snagging any 360 head and having it milled .020-.030. You obviously didn't read the articles I linked to. Cam choice is explained there. It is always better to under-cam. Stick with 250-260's gross duration with lift below .480". New springs ARE NOT optional "if budget allows".
Factory 340 cam is still a good one but the wide lobe separation (114 deg. If memory serves) was intended to spread the powerband out as much as possible for the high-winding (6400 rpm) 340. Lobe sep of 110 degrees will improve midrange torque while giving good power through 5500rpm.
 

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Discussion Starter · #11 ·
^^ ok. I honestly was starting to doubt my thought process and was coming back to ask more questions but this seems to help. Can i just keep the factory heads (the more i read, i think i have the desirable "swirl-port" design), Performer Intake, a factory Thermoquad carb, headers (1 5/8"), and a cam?? The only reason i was considering porting my heads is because the motor would be taken apart anyway for the cam installation, but honestly the more i think about it, it probably isn't necessary (the truck is just a weekender).

Also, the more i prepare for this modding I've come across a couple of other things i unsure of.
1) I want to go factory Thermoquad... however, my truck is EGR equipped. What should i do in terms of carb and ignition?? I read some guys are doing headers (no-cats), EGR-less carbs and a stand alone ignition system to bypass computer -OR- do headers (still no-cats), EGR-equipped carb and retain factory computer and ignition??

2)Depending on the answer above, which vehicle should i pull this carb off of?? Obviously it will be Chrysler for the linkage, but with a mild cam, headers and Performer intake which vehicle would have the best factory jets and such to bolt on to my 86 w150??
 

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Now you're getting it. Any TQ carb will do. If it was on a 318, it'll have a restrictor in place that keeps the secondaries from opening fully. It's easily removable. Since all those carbs were jetted as lean as possible, I'd look for one from at least a 360. Even one from a 400. If you snag one from a late 340, it's all good, you can always, easily tune it down a bit with the metering rods. Older TQs have fewer emissions ports to cap, but any will work. An early 340 unit will be the best, but also most costly. As an alternative, an Edelbrock Performer or Thunder series carb is great. Both are updated Carter designs that pre-date the TQ. Wish they'd do it for the TQ too.
If you don't have emissions to worry with, I'd block the exhaust crossovers in the heads, rendering EGR null and void. There are several ignition alternatives. There's the Mopar system, Mallory ready to run distributor, even the growing movement towards the GM HEI distributor setup, which is also essentially a drop-in unit as well. The only computer an '86 would have might be the lean burn. Doing what you're planning will remove it effectively.
I ran a 318 with the basic mods in my first car, a '69 Charger. It ran beautifully and regularly knocked down 19mpg as long as I stayed out of the carb. Back then there were fewer options. I was lucky to have an SP2-P intake, some cheap headers, and the CompCams 260 High Energy cam. Dad insisted on a new Holley 600, but nobody knew how to tune it. Once I put on a rebuilt AFB, it roared nicely and I had it tweaked in no time. The TQ is the ultimate street carb. If you are willing to deal with digging up parts (they're out there) you'll be fine.
 

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Discussion Starter · #13 ·
Well this sounds like a plan. I got some toys i need to sell before i get to drop crazy money into my free, old truck but i can't wait ;) i driving her the way she is to work tomorrow to let our quick lube shop manager criticize her (he got an 80's Ramcharger that he is obsessed with). I hoping to get her washed up and get the simple shit fixed by the end of this coming week, then i got spring break to waste an entire week on her!!! I haven't looked yet, but if this forum has it i wanna start a build thread for this baby. This is gonna be my new good looking, bad ass women with y'alls help haha
 
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