Hypothetical 318 Builds

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RustyRatRod

I was born on a Monday. Not last Monday.
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There's been a lot of 318 talk recently, so I thought what better way to have a little fun than have a hypothetical 318 built thread? Just a couple of rules. Must be stock 3.31" 318 stroke and "whatever" bore. Whatever heads, cam and pistons is fine, but no stroker. You start talkin stroker this and that or "use a 340 or 360" go start your own thread. Also, this thread is for naturally aspirated builds. No power adders like blowers, turbos and nitrous. Go start your own thread. This is to help guys with 318 builds get a good idea of what they are capable of. So with that in mind, here is my recipe for "around" 300-325HP 318 build.

I would start with a 5.2 Magnum engine since the LA platform is so old now, decent cores are getting pretty tough to find. Also, we have the advantage of a factory hydraulic setup and 1.6 rockers. With that in mind,

9.5:1 blueprinted compression ratio. Stock Magnum 1.920/1.625 360 (Thanks @66fs) valves in the Magnum heads with bowls blended nicely. If you can afford to port the rest of the way, or do it yourself, knock it out, but it's not necessary. A good quality multi angle valve job is a must.

For camshaft, I'm ASSUMING since you want a hot 318 that you're gonna want to rev it some and play around so I'm choosing a pretty stout grind. Grind #1408 on the Oregon Cam hydraulic roller list. .480 lift both sides, 224@ .050" intake and 230@ .050" exhaust, but we're gonna get them to grind it on a 106. They will do that no charge. We will use stock Magnum lifters. They last a long time, so if you find a good used set, more power to you. We'll utilize the Hughes Engines 1110 valve spring.

On rocker arms, I like adjustability and IMO, the most cost effective is the kit Hughes Engines sells.
ROCKER ARM KIT
Might be cheaper ways, but this gives you everything you need in one fell swoop and it's pretty nice.

As for intake mannyfold, I like the air gap style. The port match to the heads is important, so you'll need to include having the heads and intake port matched in the budget. Well worth the money. If you want to go further, and can do it yourself or afford it, great, but all I'm calling "necessary" with this build is the port matching. With that in mind, get the genuine Edelbrock if you want, or the chinkese knock off, it really doesn't matter.

Just like with the camshaft, I'm assuming you're gonna run this little beeotch, so I'm gonna choose a Quick Fuel Brawler 650 dual line double pumper.

On the ignition, all yall know I like the stock Mopar style electronic ignition. I recommend sending the distributor to @halifaxhops Ray and he will hook you up with a good hot ignition curve. He can even fix you up with a good, NOS quality ignition ECU box, or the other I recommend is the "HI Rev 7500" available at Jegs. I got mine off Amazon and it came in a Jegs box.

As for exhaust, again, we're not buildin a pussy 318, so this gets headers. I recommend the biggest primary tube header you can afford and also a complete 3" exhaust to the rear bumper with constant diameter mufflers "of some kind".

This should actually about cover it. You WILL have an honest 300-325HP and possibly more depending on how far you want to go with port work.

So that's my recipe for a good hot, reliable 318. What's yours?
 
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There's been a lot of 318 talk recently, so I thought what better way to have a little fun than have a hypothetical 318 built thread? Just a couple of rules. Must be stock 3.31" 318 stroke and "whatever" bore. Whatever heads, cam and pistons is fine, but no stroker. You start talkin stroker this and that or "use a 340 or 360" go start your own thread. Also, this thread is for naturally aspirated builds. No power adders like blowers, turbos and nitrous. Go start your own thread. This is to help guys with 318 builds get a good idea of what they are capable of. So with that in mind, here is my recipe for "around" 300-325HP 318 build.

I would start with a 5.2 Magnum engine since the LA platform is so old now, decent cores are getting pretty tough to find. Also, we have the advantage of a factory hydraulic setup and 1.6 rockers. With that in mind,

9.5:1 blueprinted compression ratio. Stock 1.88/1.60 360 valves in the Magnum heads with bowls blended nicely. If you can afford to port the rest of the way, or do it yourself, knock it out, but it's not necessary. A good quality multi angle valve job is a must.

For camshaft, I'm ASSUMING since you want a hot 318 that you're gonna want to rev it some and play around so I'm choosing a pretty stout grind. Grind #1408 on the Oregon Cam hydraulic roller list. .480 lift both sides, 224@ .050" intake and 230@ .050" exhaust, but we're gonna get them to grind it on a 106. They will do that no charge. We will use stock Magnum lifters. They last a long time, so if you find a good used set, more power to you. We'll utilize the Hughes Engines 1110 valve spring.

On rocker arms, I like adjustability and IMO, the most cost effective is the kit Hughes Engines sells.
ROCKER ARM KIT
Might be cheaper ways, but this gives you everything you need in one fell swoop and it's pretty nice.

As for intake mannyfold, I like the air gap style. The port match to the heads is important, so you'll need to include having the heads and intake port matched in the budget. Well worth the money. If you want to go further, and can do it yourself or afford it, great, but all I'm calling "necessary" with this build is the port matching. With that in mind, get the genuine Edelbrock if you want, or the chinkese knock off, it really doesn't matter.

Just like with the camshaft, I'm assuming you're gonna run this little beeotch, so I'm gonna choose a Quick Fuel Brawler 650 dual line double pumper.

On the ignition, all yall know I like the stock Mopar style electronic ignition. I recommend sending the distributor to @halifaxhops Ray and he will hook you up with a good hot ignition curve. He can even fix you up with a good, NOS quality ignition ECU box, or the other I recommend is the "HI Rev 7500" available at Jegs. I got mine off Amazon and it came in a Jegs box.

As for exhaust, again, we're not buildin a pussy 318, so this gets headers. I recommend the biggest primary tube header you can afford and also a complete 3" exhaust to the rear bumper with constant diameter mufflers "of some kind".

This should actually about cover it. You WILL have an honest 300-325HP and possibly more depending on how far you want to go with port work.

So that's my recipe for a good hot, reliable 318. What's yours?

I like your ground rules, but magnum valves are larger than 1.88 and 1.60 (like 1.94 and 1.62) if I remember correctly. I'll add how I would build a 318 when I get time to think about it.
 
I like your ground rules, but magnum valves are larger than 1.88 and 1.60 (like 1.94 and 1.62) if I remember correctly. I'll add how I would build a 318 when I get time to think about it.
That's right they are. I'll have to make that correction. Thank you.
 
Good one Rob. The Magnum engines are just that much better than the LA's with the roller cam, small valve stems, and all. We can add Magnum heads to an LA block if you want to mess with the pushrods and such. The Magnum exhaust ports are a bit different. I know the LA headers fit but do the ports line up?
 
Good one Rob. The Magnum engines are just that much better than the LA's with the roller cam, small valve stems, and all. We can add Magnum heads to an LA block if you want to mess with the pushrods and such. The Magnum exhaust ports are a bit different. I know the LA headers fit but do the ports line up?
I'm pretty positive they do, yes.
 
Good one Rob. The Magnum engines are just that much better than the LA's with the roller cam, small valve stems, and all. We can add Magnum heads to an LA block if you want to mess with the pushrods and such. The Magnum exhaust ports are a bit different. I know the LA headers fit but do the ports line up?

They do and they are a small(273, 318) exhaust port that flow like a large(340, 360) exhaust port. That said, I like LA heads.
 
This is a cool thread! Thanks Rob! I've had a 318 planned for quite a while now idk if I'll ever get around to building it but I got mostly everything to do it minus pistons and intake. I can't remember all the numbers I got them wrote down somewhere but it goes something like this, 318 la block factory crank and rods balanced with some kb 399 pistons, block decked to zero. Ported 360 heads milled to 65 ccs ported. Puts it around 11.5 scr. To use up that compression a big mopar purple 528 cam topped with a dual quad intake to let that big cam really suck some fuel. I think it would be an awesome sight with two big thermoquads sticking up out of the closed hood
 
They do and they are a small(273, 318) exhaust port that flow like a large(340, 360) exhaust port. That said, I like LA heads.
I prefer LA engines overall. I chose the Magnum for my version because they are easier to find in better condition since they are newer.......but as time goes by......"not by much". lol
 
Nice thing about choosing a Mag 5.2/318, is that chances are good that you can just break the glaze in the cylinders and go. Awesome way to keep it cheap and spend money on other parts.
 
Nice thing about choosing a Mag 5.2/318, is that chances are good that you can just break the glaze in the cylinders and go. Awesome way to keep it cheap and spend money on other parts.
Yep I got one I pulled out of a ram with over 200k miles the heads are cracked but the cylinder walls not so much as a lip at the top. Wonder why the magnums wear so much better than the la's? I have a la 318 with low miles like 87k iirc and it was pretty bad! Bad enough I broke all the rings and had to get a cylinder bore reamer to remove the pistons
 
Nice thing about choosing a Mag 5.2/318, is that chances are good that you can just break the glaze in the cylinders and go. Awesome way to keep it cheap and spend money on other parts.
Kinda where I was goin. lol
 
Yep I got one I pulled out of a ram with over 200k miles the heads are cracked but the cylinder walls not so much as a lip at the top. Wonder why the magnums wear so much better than the la's? I have a la 318 with low miles like 87k iirc and it was pretty bad! Bad enough I broke all the rings and had to get a cylinder bore reamer to remove the pistons
More modern ring pack is the biggest thing. The newer rings are thinner. Plus the modern oils.
 
Yep I got one I pulled out of a ram with over 200k miles the heads are cracked but the cylinder walls not so much as a lip at the top. Wonder why the magnums wear so much better than the la's? I have a la 318 with low miles like 87k iirc and it was pretty bad! Bad enough I broke all the rings and had to get a cylinder bore reamer to remove the pistons
Fuel injection controlling the tune up instead of some dude with a screwdriver, and thin rings. That’s why they wear so much better.
 
More modern ring pack is the biggest thing. The newer rings are thinner. Plus the modern oils.

Fuel injection controlling the tune up instead of some dude with a screwdriver, and thin rings. That’s why they wear so much better.
I've always wondered, once we get a Magnum and convert it to a carb., do the bores wear more like we are used to with the older engines? It seems that they probably would. Anyone have any first-hand experience?
 
This build is theoretical?
Or are we doing this on the forum as a friendly competition with a zero prize?
 
Added Couple of in car 318 builds
https://www.motortrend.com/how-to/mopp-0311-318-engine-buildup-and-dyno-test/
https://www.motortrend.com/features/mopp-0009-1985-dodge-dart/


https://www.motortrend.com/how-to/ccrp-0401-mopar-318-engine/
Magnum heads 10:1 cr comp 280h cam

Mopar 318
RPMHPTQ
3,000190332
3,500241376
4,000286376
4,500321375
4,900357382
5,000363381
5,500388371
6,000398348
6,200400339
6,500393318


https://www.motortrend.com/how-to/0810phr-chrysler-318-engine/
EQ 9.85:1 cr xe275hl

RPMTQTQHPHP
BASEPORTEDBASEPORTED
3,000335335192192
3,200342340208207
3,400351356228231
3,600365369250253
3,800374379271274
4,000379384289293
4,200378383302306
4,400375383314321
4,600376382329335
4,800375386343353
5,000372384354366
5,200367383363378
5,400361379371390
5,600355374379399
5,800350371386409
6,000345365395418
6,200341360402425
6,400329345401421

https://www.motortrend.com/how-to/318-small-block-build/
Ported 302 10:1 xe268h

RPMTEST 1TEST 2TEST 3
TorqueHPTorqueHPTorqueHP
3,000334.9191.3354.1202.3349.1199.4
3,500360.7240.4378.2252.0380.7253.7
4,000376.6286.8402.3306.4401.5305.8
4,100379.3296.1402.4314.1401.6313.5
4,500374.0320.4402.5344.9400.1342.8
4,600374.0327.6403.1353.0400.6350.9
4,700373.5334.2400.6358.4408.0365.1
5,000363.9346.4389.7371.0402.0382.7
5,500344.0360.2368.3385.7386.5404.8
5,900331.1372.0347.1390.0361.4406.0
6,000328.3375.0344.0393.0353.8404.2
6,100319.4371.0339.2394.0347.8404.0

https://www.motortrend.com/how-to/0901phr-mopar-318-magnum-engine/
ported EQ 10.5:1 solid 247/247 @ fifty

On The Dyno DTS Dyno Data Performance Crankshaft 323CI Small-Block Mopar
RPMTQHP
2,500337161
2,600350173
2,700357183
2,800357190
2,900356196
3,000351201
3,100345204
3,200339207
3,300343216
3,400356230
3,500371247
3,600385264
3,700396279
3,800404292
3,900410305
4,000415316
4,100418327
4,200420336
4,300422345
4,400421353
4,500420360
4,600421369
4,700425380
4,800426390
4,900427398
5,000427407
5,100427414
5,200426421
5,300425428
5,400423435
5,500421440
5,600419446
5,700417453
5,800415458
5,900412462
6,000407465
6,100401466
6,200397469
6,300393471
6,400390475
6,500386477

https://www.motortrend.com/how-to/mopp-0312-318-long-block-bolt-ons/
stock heads cr xe262h

HORSEPOWER SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPMBASEMOD 1MOD 2
2,000112
2,500137
3,000164193192
3,500182224227
4,000189248252
4,500186265274
5,000179271282
5,500262270


TORQUE SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPMBASEMOD 1MOD 2
2,000292
2,500287
3,000287338336
3,500272335340
4,000248326330
4500218309319
5,000188285296
5,500250258
 
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I'd do a 10.5:1 cr 318 magnum with trick flows, 750 & airgap with 230 ish roller around .550 lift on 110 basic standard fair mid built engine.

Or add tunnel ram and solid 245 .650 ish roller
 
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Goodie, I'll put something together on paper this weekend.
This is going to be fun. :D
 
I need to get my old laptop out with the Desktop Dyno program on it. :poke: :lol: :lol:
 
Any way we could throw rough costs in here even if its a pretty wide spread?
 
And the nice thing about this thread is you don't have to strive for maximum horsepower. Just a nice combination that works.
 
This build is theoretical?
Or are we doing this on the forum as a friendly competition with a zero prize?
Theoretical......hypothetical.......make believe.....whatever you wanna call it.
 
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