318 stroker

[Johnny Mac]

correct, a cammed 318 with a 4bbl is clearly no where in the ballpark of a crate cost. You and the OP had both mentioned strokers, and thats a big expense over minor bolt ons. but no big deal. keep me in mind if you need anything from a carb to a distributor, i do it all.lol

 

[Artis]

Thanks for opinions guys.

I would be glad to keep OE heads. But will see.
Im thinking about:
- Port heads ( if stays OE heads )
- better intake manifold ( suggestions? )
- 4bbl carb
- cam
- 392 crank + pistons + rods
- custom exhaust (incl. headers)
- all new gaskets, seals etc.

IMO - #s matching 318 "sleeper" with 300+ (or even more with this setup)hp is more attractive than bought and swapped anything below 440. Where's a point to buy and swap engine, when you can spend all that money in 318 and get same performance or even more, with matching numbers engine.

 

[Johnny Mac]

Thanks for opinions guys.

I would be glad to keep OE heads. But will see.
Im thinking about:
- Port heads ( if stays OE heads )
- better intake manifold ( suggestions? )
- 4bbl carb
- cam
- 392 crank + pistons + rods
- custom exhaust (incl. headers)
- all new gaskets, seals etc.

IMO - #s matching 318 "sleeper" with 300+ (or even more with this setup)hp is more attractive than bought and swapped anything below 440. Where's a point to buy and swap engine, when you can spend all that money in 318 and get same performance or even more, with matching numbers engine.

Its ambitious i'll give you that, but you're a bit off in your calculations IMO.

First off, getting the block machined is going to run you at least $1000. And a rotating assembly at least $2000, and you haven't even touched cam, heads, intake, gaskets, etc. so you're incurring a ton of labor and cost to build this "300 ish HP engine" when you only need a cam,headers,intake, and exhaust to get there.
your factory heads are going to absolutely destroy the positive effects and HP you'd normal gains from a stroker kit.
Porting stock 318 2bb heads is a waste of time, unless you're getting it done for free, or crazy cheap.

what you're talking about doing is going to run you substantially more $ than i think you're taking into account, and its unnecessary to stroke this engine for the power levels you're looking for. If you are dead set on the stroker idea, then you better throw $ in for the cylinder heads you're going to need, which will like a bigger cam, which will make your converter unusable, which will overpower the rear end and the stock trans.... you're snowballing just chasing the "392" number.

just throwing out information that i think would be beneficial to know, regardless of whatever you end up doing.

 

[rumblefish360]

I would be glad to keep OE heads. But will see.
Im thinking about:
- Port heads ( if stays OE heads )
- better intake manifold ( suggestions? )
- 4bbl carb
- cam
- 392 crank + pistons + rods
- custom exhaust (incl. headers)
- all new gaskets, seals etc.

Porting the OE 318 heads is something I generally recommend against doing. Even more so in a huge way if you stroke the engine. There just isn't enough head for the 4 inch arm. The head just doesn't have enough around it to support a good engine and decent power level.

At 390 or so cubes of a stroked 318, a stock aftermarket aluminum head still doesn't have enough, but, it will work OK for a total streeter engine. The engine will produce a lot of torque and just OK horsepower.

On a 390 cid engine, there are only a few intakes that would be good for use. From mild to wild;

Edelbrocks RPM / RPM -AG and at least a 750 cfm carb. This is really the only street or street strip intake & carb combo I would consider, at this CID level. (Perhaps more carb if the build is aggressive enough. And/or at the track more often.)

For exhaust on a B body, there are only two headers I would look at. Stepped TTI headers (and there full exhaust system) or Hooker Super Comps @ 1-3/4 primary pipe size. The Hookers fit wonderfully in a small block B body. (Unless you have a Lakewood scattersheild on your 4spd. 1 tube to be dented, passenger side, no biggie.)
TTI exhaust can be adapted to the Hookers.

Both headers are expensive.

Your cam size would have to match your converter, gear & performance goals. Recommendation with held due to uncertainty of actual goal and direction.

 

[moper]

Horsepower is all about airflow, and airflow always comes down to value (cost vs return on investment). To get 300hp, you will need at least 150cfm in the lift range of your camshaft. 175 would be better given these are street cams with relatively small resulting flow windows. The issue is the 318 heads as cast, with stock ports and valves, will just barely reach the 170 area. So while there is a reason to kep the numbers engine numbers, the expetaction of performance may force you to address the base airflow defficiencies. Another factor is torque. Torque is what gets you moving, and what you feel when the gas pedal moves. Simple mechanics: longer stroke = more torque at the same given rpm. A 300hp 318 will not be a big torque producer at rpms under 3K. It will be snappy and sound good, but it's just not that strong. So you need gearing or a looser torque convertor, or a combination of both, to make it perform and feel better. A 390" (4" stroke, 318 block) can make 300hp easy with the right heads, and make a large percentage more torque right off idle. That you will fell every time you drive the car and it doesn;t matter what gearing or convertor you have. It would work with stock stuff.
So I would suggest the OP do some serious thinking about what the car does for you, and what you want it to do moving forward, how much retiaining originality is worth to you, and how much money you have to appropriate for the entire project. Those answers allow the build to be framed and a plan to be put together.

 

[NJRR]

Horsepower is all about airflow, and airflow always comes down to value (cost vs return on investment). To get 300hp, you will need at least 150cfm in the lift range of your camshaft. 175 would be better given these are street cams with relatively small resulting flow windows. The issue is the 318 heads as cast, with stock ports and valves, will just barely reach the 170 area. So while there is a reason to kep the numbers engine numbers, the expetaction of performance may force you to address the base airflow defficiencies. Another factor is torque. Torque is what gets you moving, and what you feel when the gas pedal moves. Simple mechanics: longer stroke = more torque at the same given rpm. A 300hp 318 will not be a big torque producer at rpms under 3K. It will be snappy and sound good, but it's just not that strong. So you need gearing or a looser torque convertor, or a combination of both, to make it perform and feel better. A 390" (4" stroke, 318 block) can make 300hp easy with the right heads, and make a large percentage more torque right off idle. That you will fell every time you drive the car and it doesn;t matter what gearing or convertor you have. It would work with stock stuff.
So I would suggest the OP do some serious thinking about what the car does for you, and what you want it to do moving forward, how much retiaining originality is worth to you, and how much money you have to appropriate for the entire project. Those answers allow the build to be framed and a plan to be put together.

So what do you think the maximum HP and torque is that you can get out of a 318, how would you do it and what do you think it would cost?

 

[451Mopar]

If the engine is still in decent shape (good oil pressure and not burning alot of oil), I would just put a 4-bbl intake, 600 cfm carb, and dual exhaust on the engine. Then get a good torque converter, re-curve the ignition, and maybe spend the money on a 8-3/4" rear with 3.55:1 gears.
You would likely need these parts for and modifications moving forward anyhow, but just these few things will make a big difference on the cars performance.
Even with the stock cam and manifolds, the performance will be improved quite a bit.
Good headers, like the TTI version that don't hang under the suspension are expensive, so this area may take an unexpected bite out of the budget.
The 904 trans can take plenty of power and some racers with big blocks convert the 904 to run behind big blocks. If you plan to change transmissions, I would start looking at overdrive style like the 518.
If you decide to stay with the stock stroke, a small cam around 210-216 works good. Anything to improve head flow will help.
Going for more power than these simple changes, you should look to use aftermarket cylinder heads. I would not invest money rebuilding and upgrading the stock heads (hardened seats, larger valves, porting, cutting spring seats, ect.) you likely would have $600+ into the stock heads that could have been spent on some good flowing EQ or Indy LA X heads. Hughes engines has the Iron Ram heads for $1121. They take the standard LA intake, but use the Magnum type rocker gear and require hollow pushrods. The Indy LA X Heads are $1337, and use the stock shaft type rocker gear.

 

[451Mopar]

So what do you think the maximum HP and torque is that you can get out of a 318, how would you do it and what do you think it would cost?

Thats a really open ended question? Talking race only, filled block, high end parts with power adder (which fuel?), limited run time, assuming your looking at the ultimate strength of the stock engine block casting?

 

[NJRR]

Thats a really open ended question? Talking race only, filled block, high end parts with power adder (which fuel?), limited run time, assuming your looking at the ultimate strength of the stock engine block casting?

I guess it is pretty open ended. Let's say for street, keeping the 904 and 8 1/4 rear.

 

[rumblefish360]

And your looking for maximum HP & Tq from the 318 in a B body? Yikes! Your asking extremely broad questions without any goals listed. This is beyond wide open field. More like wide open sky at 50,000 ft!

Honestly, IMO, stroking the 318 to a 390 for 300 hp is a colossal waste of money.

A B body with 3.55's and a 904?
What's the cars weight?
What is the performance goal?
(Please don't say "I want maximum power and torque! Or go nice and fast!)

I already gave a nice and easy to follow build up in post #11.
Go the stock head route, add a better stall converter & a shift kit. It'll work with the 3.55's very nicely.

 

[toolmanmike]

Stop on over to FABO and search for 318 builds or 318 strokers. There's tons of threads about the subject.

 

[451Mopar]

I don't know what torque the 8-1/4 will take? I know of several 904's in 10-second cars which likely have over 500 rear wheel HP?
Interesting CarCraft article, 500 HP for 5K? They did not include alot of items like headers, oil pan, valve cover, main bolts/studs, ect. Most likely 8K+ by the time you get it in the car and running with fuel system and exhaust?
http://www.hotrod.com/articles/ccrp-1003-chrysler-la-engine-build/

They also mention a 662 HP supercharged 318, but I'd guess it costs 10K+?

 

[mopar 3 B]

For the money.
Steel piston, and a small turbo

 

[Artis]

4bbl + better intake + better exhaust all long - that was first plan to do, but now Im started thinking because block need some machining attention.
Heads are the weakest spot for 318engine. Whats the best cfm I can get from them with stock valves? I know its costly, but ...
And question at the end of the day is - what is more valiable these days - #'s matching stroked 318 engine or 440 in good shape from junkyard? Both engines are refreshned (gaskets, seals, rings etc)...

 

[moper]

So what do you think the maximum HP and torque is that you can get out of a 318, how would you do it and what do you think it would cost?

I would go with the cast (not the EAGLE cheapie) 4" stroker. Forged pistons only (I won't use hypers in non factory stroke engines). My builds are completely machined on a top-of-the-line Rottler CNC machining center. I'd run main studs, internally balance it. the 318 heads will not support it. Replace them with any late 60s/early 70s 340/360 heads (so appearance is the same) that have been totally refurbished including oversize stainless nailhead valves, unleaded seats, guides or liners, a 5 angle cutter valve job, & some hand blanding and gasket matching. You'll need a set of 273-typerockers or modern roller rockers, I'd run a hydraulic flat tappet cam, dual plane, and a Holley 870 vacuum secondary carb. Last time I did it (based on a 340 but that's not much different aside from initial cost and sless valve shrouding) it made 470hp based off the weight and MPH. It's currently got over 20K miles, it's 9 years old, and gets 17mpg mixed driving in an E body. Price - in todays money, probably $9-10K depending on who builds it, what they use for parts, and what they do with it prior to you picking it up (like dynoing, etc).