LA 318 w/ roller lifters&cam - Waste Of Time?

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cudaracer

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As I waffle back and forth on what to do with my 1972 318 short assy that is stock, topped with 360 heads/intake/600cfm/medium cam, I am hoping to get some real world experience with anyone who has upgraded to hyd rollers/cam & rockers. I am getting seriously conflicting opinions on this simple question, ranging from “complete waste of money” all the way to “best bang for buck.” Share your opinions, fine, but backing them with experience goes a long way.

For reference:
Waffle idea level #1 build is just rebuilding short, adding KB167 pistons, maybe rods too.
Waffle idea level #2 is the 348 stroker crank, flat Silvolites with correct comp height, rods for sure.
Waffle idea level #3 is full 390 stroker kit.


Thanks
 
You're not alone-many people are indecisive when planning what to do with their vehicles. But, like has been said time and again before, build it how you want it to perform.

What's your end goal?
What's your budget?

Keep in mind the engine likely won't be the only thing you modify if you plan on increased performance...think stall, gears, other suspension mods, fuel system as needed, possible increased cooling requirement (increased hp=Increased heat), exhaust, etc...

I liked the idea of the cheap stroker-it was different, and depending on the direction you took, could probably work pretty well.

But if you're just looking to make a 300-325 hp daily driver, rebuilding the 318 with some good parts will work well and no custom machine work would be required.
 
Half the problem of a roller cam is expense and the other half is taking full advantage of the cam. One more thing comes to mind is that unless your going to take full advantage of the roller cam, a stout solid will perform just as well.
 
Gosh I have so much to learn.
So how exactly does mechanical (roller or not) help a moderate performer? I thought it was mostly about high rpm durability. Is there perf gains?
 
OK, for roller obviously, but you also get perf gains with a simple mechanical lifter setup? Please explain, unless the answer is the ability for higher RPM's, which I already know.
Thanks.
 
cudaracer said:
OK, for roller obviously, but you also get perf gains with a simple mechanical lifter setup? Please explain, unless the answer is the ability for higher RPM's, which I already know. Thanks.
Click to expand...
Yes-even plain solid cams will make great power and usually rev like mad and don't suffer from lifter pump up like hydraulics can and often do. You typically need better springs, and need to understand a solid cam with the same exact numbers as a hydraulic will act a little different...there's another thread or six on here describing it, but I'm on my phone and the search function for the app isn't as friendly as a desktop.
 
Solids usually keep the valves open higher for a longer time-steep ramps...they allow better breathing. Roller is better still

Only thing is, an adjustable valvetrain is a must...not an option
 
If I read a book, then I would not be asking any questions ;)

So based on college tuition coming soon for kids, I can't spend near the money I wanted to originally, so i have ruled out the 390 stroker option. The cheap stroker option intrigues me not just because of it's uniqueness, but because it easily solves all my 318 issues, especially torque. Since my goal is more torque down low, then more stroke will get me there. I like that fact that it is a flat piston and less surface area as well.

Here is a fact you might not find in books,

If you reduce your combustion surface to volume area by 1%, you effectively reduce your BSFC by 1/3%.
 
Read a book.....

We can skip the basic questions that a book can answer and seriously get busy on stuff. While your question is an honest one, it is also something that should be a known all ready. The book also has that info at your finger tips instead of waiting for an answer.

Overcoming the lack of torque a 273/318 has is a matter of paying attention to the build. Whe there is only so much you can enhance and tweak, it is the little things that add up. Pay attention to the little things and it'll pay back.

The big items to Pay attention to are cam timing, compression and head selection. Followed by stall converter & gears. These big items are the game plan to work with the cars weight and taget goal of the build. Don't short sell the 318 so quickly. Or just get a 360 to build on the side.
 
To bore a 318 and stroke it works, but to do both is expensive. The 360 had a much bigger bore and stroke. If you want a roller cam, get an 1989-91 360 out of a truck or maxi van and you'll have a "bored, stroked 318 in the form of a 360". They also come stock with a roller cam. If you want, you can go with the magnum, many are putting these in older cars with minimal effort. Most of the time, a person can pick up a good running motor for about 500 bucks that can be used without rebuilding. Try stroking and boring that 318 for that!!!! And a 360 mag will be a huge torque monster when compared to a stock 318 LA
 
Thanks for the advice, but Magnum = completely new top to bottom.
Not feasible. Don’t much want to either.

I have the top end ready to go.
I am mostly contemplating what to do with bottom end.

My options have been updated to,

1. Piston (KB167) only (9.5:1 CR)
2. Piston (KB167) plus roller lifter (hyd or solid) & cam & 1.5 ratio roller rockers
3. Piston (Silvolite 318 with 1.658” comp height) & 360 crank & new rods for cheap 348 stroker

3rd option should have a nice bump in torque & displacement ( 325 / 385 hp&tq using camquest ) and excluding block prep, costs ~$1200
2nd option shows bump in torque & hp, ( 352 / 390 ) and costs ~$1200
1st option shows modest gains ( 320 / 358 ) but cheapest at about $400

So while understanding that camquest might not be the most accurate, you see that option 2 not only gives you the most power & torque, but other benefits too.

Thoughts?
 
The problem is - the top end you have is not reducing the combustion area. Just the opposite really - you'll be exceeding even the factory surface area in terms of the chamber. You will gain some by reducing the amount of iron cylinder wall exposed. but honestly that's not a huge deal.
Anyway - you have several questions of your own but you haven't answered the money one. We know the 390s out. How much can you spend to have a machine shop custom machine the cheaper parts to make the 349 viable?
IMO - the cam question is one of cost only. In the performance window of "street 318" the best bang for the buck is compression. Next is headers. Next is camshaft and you won't gain anything IMO other than peace of mind while breaking in the cam over a normal hydraulic flat tappet, or if you're looking for more uumph then go solid flat tappet.

Edit - just read the rest of your last post... I think you are oversimplifying the work to get a 349 to work. I also think Camquest is marginal at best so comparing the builds that way isn;t going to do much for you.
 
Thanks moper. The only work for the 349 is piston related, right?

And I just ran a solid roller cam with 370 / 400 hp&tq numbers.

If I add headers and SP manifold, I get 445 / 445. Not bad at all. That's with a 318.
 
Just use a 360 short block then from a 91 or older. Much cheaper than turning down a 360 crank and messing with pistons. Just not sure how your figuring a much more expensive 349 is better than a very available 360. 11 more cubes and 1/3 of the money. Your project, though...
 
At $370, I would rebuild the 318 w/the KB slugs and do a roller cam with the Magnum heads. Coat the skirts, tops, chamber, etc..... Use a RPM which has single plane top end power and low end torque like a dual plane has and headers w/-2-1-2 exhaust size.

Skip the 349 stroker and concentrate on making torque from the 318. Think before you purchase a cam for this application.

IMO, your wasting time, effort and money with the 349 build with little on the return.
 
See that’s where I’m puzzled that a 318 build is good and it is what it is, but suddenly if you want to simply add crank for more stroke & displacement ……then suddenly it’s a waste of time unless you get 4" of stroke.

hmmmmmm
 
It because it is a bang for the buck vs cube issue. Why go to a 349 when a 390 is a 41 cube differance/advantage. Or just get a cheap and readily available 360 which 42 greater than a 318! And still larger than the 349 by 11 inch's & cheaper to rebuild.
 
anything I do north of 318 cubes, is within about $500 give or take.
A 360 short block would have to be purchased, in addition to machining, rebuilding, etc.
A 349 is components added to a complete engine, along with machining, rebuilding.

I just priced out a 390 kit at www.RPMperformance.com at only $1550.
That is clearly the best bang for the buck. $100's cheaper than what I last priced. Kind of changes everything and it is back on the table.

Oh, and a 349 sounds far more interesting, than a 360, you have to admit. And I am sure they would be close enough in performance not to really take sides on.
 
I don't think any of us have to admit that a 349 sounds far more interesting than a 360...intrinsically speaking, yes...interesting. More or far more interesting than a 360? mehh...

Otherwise, it's your toy...do what you will with it, take Rumble's advice about reading some literature so you can self-educate and better understand some of the replies, and their reasoning.

Oh-add up all the known costs for whatever path you choose, then double it...that's closer to where you'll actually be when all's said and done.
 
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