318 For Fun

[Dan the man]

I'm thinking that when I started inquiring about the 318 that I might have not been going about it the correct way. I'm wanting to improve the throttle response and low to midrange torque. Most likely the 318 will never see over 5,000 rpm's, I don't want or need it to be able to spin 6,000 plus rpm's. From what I've read on here is that the smaller port heads are best for port velocity and velocity is good for torque, correct? So wouldn't speedmaster's 171cc heads be to big for what I'm wanting to do? Is there a aftermarket cylinder head ( cast iron or aluminum ) that has smaller ports? I'm thinking about running the pistons at zero deck height and wouldn't I be better off with a closed chamber heads? I know that I've been giving a lot of good advice on here but as I've reviewed some of the material it's mostly focused on more power than I even need or want. I'm not looking for a 12 second car by any means. Also wouldn't the magnum heads have to much port velocity? Now as far as the cylinder heads cracking, does this effect the performance of the build, can the cracks get worse and cause more damage later on? I've talked to a machine shop and they recommend hot tanking the block and then checking the main bearing bore alignment and once this is done with then he would check block deck height and correct it if needed by decking / squaring the block and then bore and hone the cylinders with torque plates, assembly will be balanced too. Compression ratio in around mid 9's.

 

[dano]

What do you have as a starting point? Core, heads, etc? What transmission, Auto or Manual? Is this a for a car or a truck, 4x4, etc.

The more we know about what your starting with and where and how its being used the better the answers you'll get.

 

[318willrun]

If choking an engine creates torque, Thunderhead289 on youtube put a lawn mower carb on his 302 ford. Although it seems to run ok, he did NOT add torque and killed the HP. 318 magnums have a lot more HP and torque than the LA's even with the magnum heads (same heads used on 360 magnums). I've owned both.

• P.S. - This must be somewhere around your 6th thread on this 318 build that hasn't got off the ground yet ??? Keep'n us entertained, though... LOL

 

[toolmanmike]

If choking an engine creates torque, Thunderhead289 on youtube put a lawn mower carb on his 302 ford. Although it seems to run ok, he did NOT add torque and killed the HP. 318 magnums have a lot more HP and torque than the LA's even with the magnum heads (same heads used on 360 magnums). I've owned both.

• P.S. - This must be somewhere around your 6th thread on this 318 build that hasn't got off the ground yet ??? Keep'n us entertained, though... LOL

Time for me to post "Here we go again" ?

 

[Dartswinger70]

if you are just concerned with torque or a fun seat of the pants feel ..is suggest as already stated dual exhaust and rear gears 3.91s for example. A four speed doesn't hurt either, but that combination with 3.91s is revving at 3000 RMP at 60-65 MPH from my experience, yeah it will do 100 but its revving by then...if you are more into light to light or 1/8 mile and not into top speed I'd get some rear gears... I wont get too into my personal thought s on 318...unless ya really wanna hear(read) it I don't dislike them really but I'd swap it out for a 340-360 and be done ,and Id consider it money well spent before dumping the $$$ into a LA 318.

 

[toolmanmike]

if you are just concerned with torque or a fun seat of the pants feel ..is suggest as already stated dual exhaust and rear gears 3.91s for example. A four speed doesn't hurt either, but that combination with 3.91s is revving at 3000 RMP at 60-65 MPH from my experience, yeah it will do 100 but its revving by then...if you are more into light to light or 1/8 mile and not into top speed I'd get some rear gears... I wont get too into my personal thought s on 318...unless ya really wanna hear(read) it I don't dislike them really but I'd swap it out for a 340-360 and be done ,and Id consider it money well spent before dumping the $$$ into a LA 318.

I wondered how long it would be before someone mentioned a 340 or 360.

 

[Dartswinger70]

I wondered how long it would be before someone mentioned a 340 or 360.

340/360 is the gold standard Performance small block. now all that aside, it seems the OP wants to do this with a 318, he mentioned low RPM and torque.

I think I would do this in this order.
1. Dual exhaust
2. rear gears
3. 4 barrel (with stock cam)
4. cam shaft swap

i would do these things ona at a time then test/tune and measure improvement.

I would go no further and spend no more than this if it came to heads and pistons I'd swap in a 340/360 or a magnum . again my $.02 and I'm sure I'm wrong to someone with more time and $$$ to invest in a 318.

 

[Dan the man]

If choking an engine creates torque, Thunderhead289 on youtube put a lawn mower carb on his 302 ford. Although it seems to run ok, he did NOT add torque and killed the HP. 318 magnums have a lot more HP and torque even with the magnum heads (same heads used on 360 magnums).

• P.S. - This must be somewhere around your 6th thread on this 318 build that hasn't got off the ground yet ??? LOL

I'm sure it is, I don't want to spend money on cylinder heads that would serve my purpose. 318 magnums have good power and torque but at what rpm's? This is going to be semi daily driver and as it's intended goals it most likely will not see over 4,500 rpm's. I don't want to spend money on parts are intended for higher rpm

Time for me to post "Here we go again" ?

You can post that if you want to

 

[318willrun]

I'm sure it is, I don't want to spend money on cylinder heads that would serve my purpose. 318 magnums have good power and torque but at what rpm's? This is going to be semi daily driver and as it's intended goals it most likely will not see over 4,500 rpm's. I don't want to spend money on parts are intended for higher rpm

You can post that if you want to

off idle. magnums don't redline at a high rpm. And, every magnum was put in a truck, SUV, or full size vans... not high rpm race cars.

 

[Dan the man]

if you are just concerned with torque or a fun seat of the pants feel ..is suggest as already stated dual exhaust and rear gears 3.91s for example. A four speed doesn't hurt either, but that combination with 3.91s is revving at 3000 RMP at 60-65 MPH from my experience, yeah it will do 100 but its revving by then...if you are more into light to light or 1/8 mile and not into top speed I'd get some rear gears... I wont get too into my personal thought s on 318...unless ya really wanna hear(read) it I don't dislike them really but I'd swap it out for a 340-360 and be done ,and Id consider it money well spent before dumping the $$$ into a LA 318.

It doesn't make sense to me to buy a 360, what's wrong with using what someone already has. For what I'm wanting to do with it a 318 should be more than enough. Let's see what someone finds wrong with this combo, 600 carburetor, performer intake, headers, 2 1/4" mandrel bent exhaust system, 3.55 gears, 1,800-2 400 stall speed converter. Howard's 255 / 261 cam. Cylinder heads ?

 

[Dartswinger70]

Just some quick specs I ripped from Wikipedia...

At the time of its introduction, the 5.2 L Magnum created 230 hp (172 kW) at 4,100 rpm and 295 lb⋅ft (400 N⋅m) at 3,000 rpm.

From ALLPAR:


318 LA HP 230@4400 RPM

Torque 340 @ 2400 RPM

according to these numbers the LA engine is the torque winner...

 

[Dan the man]

Just some quick specs I ripped from Wikipedia...

At the time of its introduction, the 5.2 L Magnum created 230 hp (172 kW) at 4,100 rpm and 295 lb⋅ft (400 N⋅m) at 3,000 rpm.

From ALLPAR:


318 LA HP 230@4400 RPM

Torque 340 @ 2400 RPM

according to these numbers the LA engine is the torque winner...

That's more like what I'm looking at getting

 

[Dartswinger70]

It doesn't make sense to me to buy a 360, what's wrong with using what someone already has. For what I'm wanting to do with it a 318 should be more than enough. Let's see what someone finds wrong with this combo, 600 carburetor, performer intake, headers, 2 1/4" mandrel bent exhaust system, 3.55 gears, 1,800-2 400 stall speed converter. Howard's 255 / 261 cam. Cylinder heads ?

I would say do it and post the results here for the next guy to know what to expect I already stated my experience with my 318, but I knew I wasn't keeping that engine I had a 340 on the stand so I didn't do much just the duals, cam, 600 Holley and 3.91s RPM wise I hit the ceiling pretty quick meaning I could tell when the engine stopped pulling. Looking back I wish I would have kept the stock 318 cam and ran that before throwing in the Summit piece just to see what the difference may be between the two. I can say the torque was there but not the top end so much I would admit the 3.91s may have been too low a gear.

 

[Dan the man]

That's more like what I'm looking at getting

I think that everyone has given me good advice, but I still need to know what would be the best way to go for the cylinder heads, I think that I need port velocity more than high rpm use

 

[318willrun]

That's more like what I'm looking at getting

I can't even get myself to answer certain people, but there was a time when engines boasted GROSS hp, and in later times (like after 1971) they were measured in NET hp. The LA 318 produced 150 hp in 1972 when using NET hp. The 318 magnum produced 230 NET hp. And the LA torque fell to 260, while the magnum had 295. so much bad info gets posted... lol But I can't play anymore.... chinese torture LOL Dan, I wish you all the best buddy

 

[Dartswinger70]

I think in terms of stock 318 bottom end you would run stock 318 heads, anything else in terms of aftermarket will have bigger combustion chambers dropping your compression ratio, if you can add higher compression pistons , you could run Edelbrocks etc. the cc size of the chamber is what you'd need to know OR get into the porting of the stock heads like some do here.

Open chamber LA 318 heads cc at 67-68 ccs while the 340 heads cc at 68-72 so its a big drop in compression. I was going to run 360 heads on my 318 untill I realized the drop in compression. Heads are a concern and do you research but you may find running the stock heads is the way or maybe with some porting for the velocity you are mentioning.

 

[66fs]

I'm thinking that when I started inquiring about the 318 that I might have not been going about it the correct way. I'm wanting to improve the throttle response and low to midrange torque. Most likely the 318 will never see over 5,000 rpm's, I don't want or need it to be able to spin 6,000 plus rpm's. From what I've read on here is that the smaller port heads are best for port velocity and velocity is good for torque, correct? So wouldn't speedmaster's 171cc heads be to big for what I'm wanting to do? Is there a aftermarket cylinder head ( cast iron or aluminum ) that has smaller ports? I'm thinking about running the pistons at zero deck height and wouldn't I be better off with a closed chamber heads? I know that I've been giving a lot of good advice on here but as I've reviewed some of the material it's mostly focused on more power than I even need or want. I'm not looking for a 12 second car by any means. Also wouldn't the magnum heads have to much port velocity? Now as far as the cylinder heads cracking, does this effect the performance of the build, can the cracks get worse and cause more damage later on? I've talked to a machine shop and they recommend hot tanking the block and then checking the main bearing bore alignment and once this is done with then he would check block deck height and correct it if needed by decking / squaring the block and then bore and hone the cylinders with torque plates, assembly will be balanced too. Compression ratio in around mid 9's.

Sounds like a stock 5.2 magnum would be the best choice. Not all Magnum heads are cracked. I have a pair for my 5.2 Magnum if I ever put it together. I won't spend the money on aftermarket heads. Maybe 302 heads on an LA engine. In reality the cam sets how an engine will perform, the better the heads the more it will perform. What kind of gas do you want to run? That will set up your cam and piston choices.

 

[Garrett Ellison]

Well, at least you got it right with the cam!
Howards Cams, Hydraulic Flat Tappet Camshaft, Chrysler SB 273-360/318, 208/214 @ .050, .479/.494, 110 LS - Competition Products
I would probably order one while the ordering is good. Last time I checked, cam cores weren't exactly raining out of the sky. I would probably go with some 234 closed chamber heads and install 11/32 stem 1.94/1.60 chevy valves with a good three or four angle valve job. Use KB167 pistons and these head gaskets.
NOS Chrysler Dodge mopar head gasket set PN 2806984 318 360 60's 70's | eBay
I probably wouldn't put in a converter looser than 2200 rpm.

 

[PRH]

I wonder if this is another one of those “actual” builds.

There sure seems to be a lot of users with the same name......Dan something....... and they’re all asking the same basic question.

 

[Dartswinger70]

I wonder if this is another one of those “actual” builds.

There sure seems to be a lot of users with the same name......Dan something....... and they’re all asking the same basic question.

I think he started two threads because we or I derailed the first one down the 340 /360 train tracks...

For the record I don't have issue with the LA 318. I am from the days of buying them for cheap or picking them up for free so I don't know if I'd dump a bunch of coin into one...

 

[rumblefish360]

It doesn't make sense to me to buy a 360, what's wrong with using what someone already has. For what I'm wanting to do with it a 318 should be more than enough. Let's see what someone finds wrong with this combo, 600 carburetor, performer intake, headers, 2 1/4" mandrel bent exhaust system, 3.55 gears, 1,800-2 400 stall speed converter. Howard's 255 / 261 cam. Cylinder heads ?

Can I get a link to the actual cam?

I’d run a “H” piped dual exhaust @ 2-1/2.

The 171 speed masters would be a nice upgrade over the factory iron heads everywhere in the lift range and power band.

It’s difficult to put to big of a head on an engine.
Or you just do something totally insane.

 

[Garrett Ellison]

Can I get a link to the actual cam?

Howards Cams, Hydraulic Flat Tappet Camshaft, Chrysler SB 273-360/318, 208/214 @ .050, .479/.494, 110 LS-Competition Products

 

[rumblefish360]

WOW! That is a 1 step above stock, actually, not even, just the next size up. Ridiculous!

Use stock cylinder heads with that cam.

 

[273]

How much hp you after?

Seem like you want the best idle to 4500 rpm maybe 5000 rpm max powerband. Right ?

Idle to 2500 rpm is hard to improve over stock. Lower pumping loss, friction, efficiency like Cr can help but overall best you can hope for is least loss or little gain while trying to gain in the 2500-5000 range which shouldn't be to hard, cam choice would be the biggest factor. Hp is torque over time (rpm) and torque is mainly a product of displacement so the easiest way to gain in a fixed powerband is displacement either Naturally aspirated and or artificial like blower, turbo. Even rpm is a form of displacement, you Rev 10% more you displace 10% ish more air.

As for velocity, to make power you need to increase air flow 'cfm' and efficiency best you can do on that front is bump Cr, as for air flow exhaust and dual plane 4bbl are a given and generally no downside. Which leaves heads and cam, modern hemi an LS engines use head flow with mild cams to get streetable power, restrictive heads with bigger cams for same power is a less street friendly way.

So say your looking to make 1 hp per Cid which is a healthy but streetable engine if done the right way. So say your cam gonna be a mild 210 @ 0.050' .475-.500' lift 110-114 you need a head that will flow enough to make 325 hp with that cam, a stock 318 head wouldn't magnum should, speedmaster easily. Not saying velocity ain't important but people over worry about. In a full throttle run you spend little time under 2500 rpm, driving at speed needs very little hp, so it only under light to mid acceleration could be a problem, I'd say it would be worse with restrictive heads and bigger cam, if you go with gears in a light car a mild stall even less of an issue. Were not talking fully ported W2 here.

 

[Garrett Ellison]

Some ported 234 or 973 casting heads with larger valves would keep the port velocity up and flow pretty decently, but a set of bare speedmaster iron magnum heads would make a better starting point. It is possible to adapt an LA intake manifolds for use with magnum heads (or maybe even drill magnum heads on a mill to accept an LA intake?), but the assault racing air gap intake will make all the torque you could ever need. I've done it on a 318 magnum with the smallest cam upgrade imaginable and it made earth mover levels of torque. Confirmed by over 10,000 pound towing use in a relatively high geared truck. With a magnum head the selected cam becomes a .511/.526 piece by virtue of the 1.6;1 rockers. But what exactly are you planning on putting this into and what gears are you planning on running? I ask because the goal for the RPM limit is in the realm of a 1/4 mile pavement track pure stock car. I don't know of any quickly accelerating street builds that don't get spun past 5,000 at some point and then it becoming pretty commonplace from there.