Mild LA 318 Cam Recommendations from Those Who Know

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Torqueflite

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I spent the last couple days reading all the 318 cam threads in the search, but none I found comes close to my setup. I'd appreciate hydraulic flat-tappet cam profile or brand/number input from those of you who really know mildly hopped up LA318s. Keep in mind I haven't purchased any engine parts yet, so the below details are from my current spreadsheet but can change if needed.

The backstory is that my wife and I are building her a car. We are finishing a 1940 Ford coupe with an aggressive 383. Long story short, the engine is too aggressive and the car has too many blind spots for my wife's comfort. She won't drive it, which sucks for her. We picked up a 1926 Dodge roadster, and she wants to build it in a mid-60's land-speed aesthetic style like someone dropped a 273 Commando in it. I already have a solid 318 core, so we'll work with that. Mainly street, low-rpm driving. Not much freeway. Weekend flogging with me driving out on the prairie away from the fuzz. The car will likely run quicker than 14 seconds at Bandimere Raceway (1/4 mile) to where I'd need a rollbar; that's not going to happen for aesthetic reasons, so it likely won't see much track time despite my disappointment.

The specs:
-1926 Dodge roadster, highboy, comes in at approx. 1,800 lbs wet on paper.
-1976 non-lockup 904 I'm rebuilding with upgraded Alto clutches/band, not like we'd plant enough torque to break a stock setup. Factory valve body with some tweaking for crisper shifts.
-Factory stall converter (around 1,800 rpm). I'm happy to adjust the stall for the cam.
-Posi differential currently with 3.0:1 gears. I'm happy to adjust gearing for the cam. 3.31 or 3.55 might work better with less torque, but the car is very light.
-Likely around 30" - 32" tall tires, so not too tall.
-1970 318 block, freshly bored to 323 cid.
-KB167 pistons should clearance at .001" in the hole. Not going to worry about zero-decking.
-Likely factory rods unless they require enough machine work to justify buying new forged.
-Factory crankshaft.
-1970 #675 heads with 1.78"/1.50" valves that look like they will lap in on the cheap. I'll be porting the heads per Justin's sticky thread because I like that kind of work.
-Assume 8.3 static CR at sea level, pump gas friendly: With a .028" head gasket and 5cc valve reliefs, static CR should be 9.3 - 9.5 assuming a head cc between 67 and 69. Keep in mind my wonderful 5,600' elevation knocks off approx. 1 whole point of compression when calculating dynamic.
-Edelbrock Performer or Offy dual-plane single four-barrel intake. No spacer unless you say it will like one with the cam you recommend.
-Likely a de-jetted 600cfm Holley 4160 or Edelbrock/Carter.
-Pair of factory passenger-side exhaust manifolds (block-huggers) with some porting. I might be open to headers, but the factory manifolds would likely be more mid-60's period-correct and fit inside the tiny engine compartment. Plus, I already have them.
-2" or 2-1/4" dual exhaust with something like super turbo mufflers.

What are you thinking would be a good cam profile for this setup? Thanks.
 
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As you know by reading the 318 cam threads, there is no magic bullet cam for a 318. You already know that you don't need a maximum horsepower cam because that's not the type of teen you are building. Something that will work with the stock converter, manifolds, and gears would be good. This will be another fun "318 cam" thread as it unfolds.
 
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Factory 340 grind or one very close to it
Agree. On a mild street 318, I stay pretty old school. I really like the old DC street hemi grinds- they came in a couple of subtle variations over the years, but they all performed very well in a mild LA. They have some good pop to them, but are still very driveable for the wife. And in your little roadster, that'll keep things interesting for years to come.
 
Factory con rods are forged....
New con rods are more than likely cheaper than fixing the old rods.

A cam without changing the gears or converter would yield at 218@050. Increase duration @050 by 4-6* per axle ratio as the ratio number climbs higher.
(224/226 intake for 3.23, 228/230 intake for 3.55’s, adjust the converter as necessary.)

Exhaust should be 2-1/2, if it fits.

Test the car with a verity of spacers as there could be a performance improvement.
 
FYI, I have ran a dozen or so cams on the dyno program and although they aren't the most accurite, The mild cams were all about the same as far as HP and torque on a basic stock teen.
The biggest cam I tested (staying below 230° duration) is the Hughes Whiplash #SMC1326AL 213/226° .480/.516 cl 109°. It produced good numbers but it is on the edge for a stock converter.
Hughes Engines


@RustyRatRod recommended the Comp 255DEH but I can't find it listed anywhere. Like it has been discontinued.
Edit: 203/219° .422/.462 ls 110°
 
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FYI, I have ran a dozen or so cams on the dyno program and although they aren't the most accurite, The mild cams were all about the same as far as HP and torque on a basic stock teen.
The biggest cam I tested (staying below 230° duration) is the Hughes Whiplash #SMC1326AL 213/226° .480/.516 cl 109°. It produced good numbers but it is on the edge for a stock converter.
Hughes Engines


@RustyRatRod recommended the Comp 255DEH but I can't find it listed anywhere. Like it has been discontinued.

For some reason, you have to either call the vendor or Comp direct for the DEH grinds now. It has to come straight from Comp now. I have no idea why.
 
FYI, I have ran a dozen or so cams on the dyno program and although they aren't the most accurite, The mild cams were all about the same as far as HP and torque on a basic stock teen.
The biggest cam I tested (staying below 230° duration) is the Hughes Whiplash #SMC1326AL 213/226° .480/.516 cl 109°. It produced good numbers but it is on the edge for a stock converter.
Hughes Engines


@RustyRatRod recommended the Comp 255DEH but I can't find it listed anywhere. Like it has been discontinued.
Edit: 203/219° .422/.462 ls 110°

Thanks for the link @PRH. Interesting that the 2 cams I listed above are quite close power and torque wise but the Comp should be easier on the valve train.
 
This is what I installed in my latest 318 project.Looks like rumblefish360 and I are on the same page. Grind # CRS 268H-10
Comp Part# 20-212-2 Gross lift both intake and exhaust .454
Duration at .050 is 218 I and 218 E
Lobe separation 110
Put it in a 63 Belvedere for a fun cruiser.Plenty of power and sounds good too.
 
Are you wanting a smooth idle , a little cam sound? Being in Colorado is tough so a smaller exhaust like you mentioned will be good and some headwork will allow you some useable upper rpm. Dual plane intake , I would just pick the smallest cam that fits needs , if you feel the need to go bigger I would add a converter like a tight 2600-2800 for a cam that uses the phrase largest with stock converter simply because of the thin air.
There are many styles of split pattern 260-268 ish (or smaller)cams that would work well , pick one according to your needs.
 
This is what I installed in my latest 318 project.Looks like rumblefish360 and I are on the same page. Grind # CRS 268H-10
Comp Part# 20-212-2 Gross lift both intake and exhaust .454
Duration at .050 is 218 I and 218 E
Lobe separation 110
Put it in a 63 Belvedere for a fun cruiser.Plenty of power and sounds good too.
Any videos so we can hear what it sounds like?
 
Thanks for the input everyone. Here's what we have so far in the thread:

Cams.jpg


I'm thinking it would be wise to keep the SLA as tight as possible to help with the compression since I'm fighting elevation, yes? The Comp 20-212-2 (row 4) looks promising in that regard and for a budget build.

Looking through Lunati's catalog, I see this potential too.
10200206
218/218, .457/.457, 110SLA, 1,500-5,300rpm

Much above those numbers and I'd need higher compression, higher stall, shorter gears it seems.
 
I vote for 3.21/3.23 gears. If running the regular Edelbrock performer, deep porting it to 360 gasket match is worth some improvement. I would imagine even more so at that altitude. A set of magnum manifolds or shorty headers may work in your engine compartment and definitely be worth some power. At this weight and performance level, I would absolutely go with a Crower 267 HDP. Very smooth and drivable with a nice sound at idle but plenty of torque for 31 to 32 inch tires with 3.21 gears.
Mopar Hydraulic Flat Tappet Camshaft
 
I vote for 3.21/3.23 gears. If running the regular Edelbrock performer, deep porting it to 360 gasket match is worth some improvement. I would imagine even more so at that altitude. A set of magnum manifolds or shorty headers may work in your engine compartment and definitely be worth some power. At this weight and performance level, I would absolutely go with a Crower 267 HDP. Very smooth and drivable with a nice sound at idle but plenty of torque for 31 to 32 inch tires with 3.21 gears.
Mopar Hydraulic Flat Tappet Camshaft

Magnum exhaust manifolds are out since they didn't exist in the 60s, but shorty headers are an option. Fooling with headers is likely not worth the money and hassle of getting them to fit and work with the headpipes since the build is already leaving performance on the table by design.

As far as porting the 318 intake runners to 360, most of the garage porting threads I've read on FABO advise against using 360 intake runners on 318 heads because the mismatched runners will create a disruptive bottleneck and type of Venturi effect when entering the 318 head runners. Wouldn't it be better to keep the velocity consistent by running 318 runners from the plenum to valve pockets, port matching to a 318 gasket of course?

The Crower 267:
218/222, .474/.485, 112SLA.
Crower recommends a higher-than-stock stall converter and 9.5 static CR, so I'd be concerned with over-camming with my 8.3 CR. Have you used this cam on an 8.5ish static CR 318 with success?
 
Yes, my mistake, badly overcammed. For whatever reason, the 8.3:1 "real world compression ratio" didn't set in. I would go with one of these two grinds in that instance.
Mopar Hydraulic Flat Tappet Camshaft - Beast - Hydraulic Flat Tappet - 273, 340, 360 & 1967-up 318 LA - Mopar/Dodge/Chrysler - Camshafts
Mopar Hydraulic Flat Tappet Camshaft - Beast - Hydraulic Flat Tappet - 273, 340, 360 & 1967-up 318 LA - Mopar/Dodge/Chrysler - Camshafts

As far as the manifold mismatch, I used to prescribe to that school of thought. But after seeing the difference before and after the deep port match in a couple of hydraulic roller cam 318s it actually makes more power all the way from idle on in back to back testing. And that's in heavy 4x4 trucks with big tires and modest gearing. FWIW, there's some magazine small block intake flow testing on line that shows the factory iron 340 intake flows more air than the unmodified performer with 318 port size at the exit flange. But with that bottle neck removed and the performer opened up to a felpro 1213 gasket match, it flows about 20 cfm more. Of course, that gets necked down at the head anyway, but it seems to work better with all the turbulence concentrated right at the pushrod hump instead of it starting several inches ahead of it inside of the manifold flange.
 
what you are missing are normalized seat durations
looking at your list the clear winner is the shorter lunati
just looking at how much shorter @.050 and the lift
340 cam would suck on a 8.25 motor- it's way bigger
you want the best get mike jones 256@,006 cam has 460 lift
that crower post 19 needs more compression like 10:1- like the 340 cam
comp has NO grinds that work for you
can't tell about hughes without seat durations but looks like too much duration
 
I did quite a bit of research back about 15 years ago for something that provided a performance gain and possibly an MPG gain without sacrificing low end and with as little modification to other areas as possible.

What I came up with on paper was the Comp XE 256.

I recently acquired one but have yet to install or run it.

Since my research, I've heard from a couple different people that the Lunati version is better "under the curve".

Theoretically, you could install the Comp 256 with no other mods- gear, converter, machine work to heads, even springs.
Since it's a dual pattern, it doesn't even need headers. I'd run 2/2.25/2.5 duals, though.
The factory said dual exhaust was worth 20HP on a 318, I'd take that.

I always question why people recommend over .500 lift cams for "one step above stock" 318 builds.
 
I did quite a bit of research back about 15 years ago for something that provided a performance gain and possibly an MPG gain without sacrificing low end and with as little modification to other areas as possible.

What I came up with on paper was the Comp XE 256.

I recently acquired one but have yet to install or run it.

Since my research, I've heard from a couple different people that the Lunati version is better "under the curve".

Theoretically, you could install the Comp 256 with no other mods- gear, converter, machine work to heads, even springs.
Since it's a dual pattern, it doesn't even need headers. I'd run 2/2.25/2.5 duals, though.
The factory said dual exhaust was worth 20HP on a 318, I'd take that.

I always question why people recommend over .500 lift cams for "one step above stock" 318 builds.
Exactly. It's easy to over-cam a stock 318. A 4 barrel with some dual exhaust and a cam with a max of about 225°@.050 and .450-.475 is about all the further you should go. .500+ lift with low duration get's you aggressive ramps and noisy valvetrain.
 
I’m also partial to the MP RV cam for this, especially if you stay with gears in the 2.94-3.08 range and 31-32 inches of tire. This is effectively like having gears closer to 2.76. It’s probably overkill for low rpm torque at your weight. But I definitely consider it in the zone of “one step above stock”. It would work exceptionally well here.
Mopar Perf. ''Purple Shaft'' Hydraulic Camshaft Kit
 
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I’m also partial to the MP RV cam for this, especially if you stay with gears in the 2.94-3.08 range and 31-32 inches of tire. This is effectively like having gears closer to 2.76. It’s probably overkill for low rpm torque at your weight. But I definitely consider it in the zone of “one step above stock”. It would work exceptionally well here.
Mopar Perf. ''Purple Shaft'' Hydraulic Camshaft Kit
Looks like a good one.

mopar cam spec.jpg
 
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