920 heads - What Cam?

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perko

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Hello,
I was starting to replace a leaky timing cover gasket and realized that I'm half way to a cam swap. I was looking for cam suggestions, but haven't really found any good threads on my setup. if you could be so kind.

I've got a 73 duster
1967 318 out of a charger, this means it came with the unusual 920 heads (one or 2 years only on the La318?) and is supposed to have higher compression.

I'm wondering what cam suggestions people have. I just drive it around when the weather is good and to go mountain biking. I would like a little bit of a lope to the exhaust note. Also, I've done one cam swap years ago so I don't really remember it. do you think its worth the extra effort? Thank you
 
Call oregon cam and tell them what you want to do. Go with their suggestion and you won't be disappointed.
 
Replacing a stock cam is almost always worth the effort. But you have to define your goals. If you’re just after a little lope and don’t want to do a converter or gear swap, I’d stick a comp xe268 in it. I have one in a 70, (9.2:1 advertised) 318 and it runs good, sounds good and doesn’t feel like it gave up anything down low. Problem is they’re out of stock pretty much everywhere.

Xtreme Energy 224/230 Hydraulic Flat Cam for Chrysler 273-360
 
A cam that will work with your compression, engine size, stall converter, cars weight, gear ratio and tire size to cruise in the rpm range your intending.


If you could answer the gear ratio and tire size, I can suggest a cam duration that will work with a stock converter and a car weight of 3500 which is a consideration of full of gasoline and you inside.

With that assumption, a cam duration @.050 of 216*’snis about as high as you want to go.
The problem with a bigger cam or duration of 216@050 is the sluggish take off you’ll have with the 2.76 gears even with the stock tire size.

If there is something different about your set up and if the converter will change, let me (us) know.
 
Keep in mind the factory 318 valve springs aren’t suitable for pretty much any aftermarket performance camshaft …….especially if they’re 50+ years old.

Any cam swap should include a spring replacement.
 
The gears are 3.21 (8 1/4)
The tires are stock sized or pretty close to.

I intend to replace the springs as well.

pretty sure its just the stock converter. its got a 904 transmission now, but I do have a spare 727.

Thanks for the help.
 
perko said:
The gears are 3.21 (8 1/4)
The tires are stock sized or pretty close to.

I intend to replace the springs as well.

pretty sure its just the stock converter. its got a 904 transmission now, but I do have a spare 727.

Thanks for the help.
Click to expand...
The 904 will require less hp to operate, keep that trans. It’ll save you from headaches.

W/the 3.21 gears and stock tires, a cam between 218 & 224 @050 is as larger as I would go duration wise. The 224 would like more stall than stock for sure. 26/2800 or more gear.

The 218 will make power to about 5K with stock heads. Upgraded heads will allow another nice and usable 500+ rpm to about 5500 rpm.
The 224 is like above, just add 500 rpm. Power to about 5500 with stock heads, upgraded heads will add another 500+ rpm to allow 6,000 rpm.

A head like a RPM will do it just fine.

Been there/done that.
 
I used a comp XE250H in a similar setup - mid 70s 318 with ported closed chamber truck heads (very similar to the 920 castings) edelbrock performer manifold with 625cfm carter AFB, headers and 2.92 gears. Good power bump from stock but nothing crazy, it was a pretty good setup for a low buck daily driver.
You could easily go 1 size bigger on the cam (XE256H) seeing as you have a early 318 it should have taller pistons than the later stuff so you should have a little more compression, the 3.23 gears will also help. Comp 901-16 spring will do you for either cam.
You don't have to use a comp cam but something with similar specs will work well.
 
perko said:
thanks for the info. does anyone have any specific brands/cams they suggest?
Click to expand...
No matter the cam manufacturer, proper break in procedure is the critical component. Start with making sure the lifters rotate in there bore as you install them and then again when the heads are on and the pushrods installed with the rocker arms.

If there not rotating, STOP! Figure out why.

Then, with everything installed, grab a buddy and have him spin the drill with an oil pump priming shaft on it to send oil everywhere making sure there’s pressure everywhere. YOU will turn the engine over by hand to allow oil everywhere and up to the rockers. The oiling is timed so don’t panic when oil doesn’t instantly appear at the rockers. Turn the engine slowly.

Then line up the cam lobes, the bottom of the lifters, pushrod ends and rocker tips.

I like the “Isky” cam lube best because it sticks to the cam and stays there!
 
Definitely keep the 904. To change you would need a new driveshaft and a converter. If the 904 starts acting up, you can pretty easily solve any issue.
 
Do you realize that with 3.21 gears, 26" tires, and an A904, your WOT mph is gonna be ~50 mph in First gear, and 84 in Second, both at 5500rpm@10% slip..
So, on the way to the speed limit, yur only gonna hit the powerpeak once.
And
On the 1-2 shift, the Rpm is gonna drop from 5500 to around 3250, which is waay off a 340 cam. which is not gonna wake up until IDK maybe 4000@ 60mph. Which means that from 50 to 60, your reduced-pressure-318 is gonna be a lil all talk/no action.
Almost everybody here will tell you that you won't notice it, but they're wrong. I mean the 340 cam will drop your cylinder pressure about 20psi, This will be most noticeable below 3000 rpm, but the softness carries right on up until the engine hits Peak-Efficiency and the power increase will pale in comparison to your expectations. So the reason you don't notice it because it is all soft, just less soft at rpm.
I mean everyone here will tell you that an 8/1 360-4v with a 340 cam, in 1974 DartSport, was a sucked out slug.
But those same people will tend to pump up the reputation of an 8/1 318-4v with the same cam, giving it glowing reports.
I swear there is no pleasing some of these clowns.

Do yourself a favor; the stock cam that is in your 67spec engine, is the right cam for those 3.21 gears. If you need a lil more oomph on take-off, just get a higher-stall convertor; at least a 2800, more if it's a city-only car.
And for the love of all that is good, do NOT install a factory 340 cam or any cam with a 114 LSA, which is nothing but a pressure bleeder to a 318.
End rant
 
AJ/FormS said:
And for the love of all that is good, do NOT install a factory 340 cam or any cam with a 114 LSA, which is nothing but a pressure bleeder to a 318.
Click to expand...
Depends on where you close the intake valve. As always run more comp.....
 
you sound a little more cruiser than bruiser, and not looking to hit your power peak at 5K while you bang shift to the speed limit. i'm *guessing* that you've got a 4bbl carb w/ dual exhaust.

if not, no biggie. these will still work, but they'd work more better-er with the usual hot rod things and stuffs.

melling 23103 is basically a 360 2bbl replacement cam but with a slightly more modern grind.
.410/.412 & 278/272 [248/256] on a 110 center

isky 16012526 is .425/.435 & 256/262 [202/208] on a 110 center (they sell several similar grinds in the sub .500 lift in split and single pattern with close to the same duration but ranging from 108 to 112 centers)

howard's street force 1 710011-12 is very similar to the isky with .420/.430 259/267 [205/213] on a 112 center, basically trading a whisper of lift for duration but the 112 center kinda bums me out. not a deal breaker tho.

if you can find one... MP4452757 is the jam. it's .410/.425 248/256 [211/218] on a 110 center

i've run all of these cams in warmed over 318's with stock heads and dual plane manifolds topped with small 4bbls and they all performed well. they're not world beaters that are gonna win street races, but they all lit up the tires and gave a nice boost of useable power for decent drama free motoring.

i've also installed a bunch of 340 cams in 318's and they work fine too.

additionally, melling 23103 or SPD-22 (340 cam) are in stock at several places and you won't have to wait until like, may to get your project wrapped up.

​

 
Cams just don't add to top end, stock cam sucks you don't need to go too big to get decent gains, xe250h or xe256h or something similar from another company.

Or you can regrind the stock cam.
 
AJ/FormS said:
Do you realize that with 3.21 gears, 26" tires, and an A904, your WOT mph is gonna be ~50 mph in First gear, and 84 in Second, both at 5500rpm@10% slip..
So, on the way to the speed limit, yur only gonna hit the powerpeak once.
And
On the 1-2 shift, the Rpm is gonna drop from 5500 to around 3250, which is waay off a 340 cam. which is not gonna wake up until IDK maybe 4000@ 60mph. Which means that from 50 to 60, your reduced-pressure-318 is gonna be a lil all talk/no action.
Almost everybody here will tell you that you won't notice it, but they're wrong. I mean the 340 cam will drop your cylinder pressure about 20psi, This will be most noticeable below 3000 rpm, but the softness carries right on up until the engine hits Peak-Efficiency and the power increase will pale in comparison to your expectations. So the reason you don't notice it because it is all soft, just less soft at rpm.
I mean everyone here will tell you that an 8/1 360-4v with a 340 cam, in 1974 DartSport, was a sucked out slug.
But those same people will tend to pump up the reputation of an 8/1 318-4v with the same cam, giving it glowing reports.
I swear there is no pleasing some of these clowns.

Do yourself a favor; the stock cam that is in your 67spec engine, is the right cam for those 3.21 gears. If you need a lil more oomph on take-off, just get a higher-stall convertor; at least a 2800, more if it's a city-only car.
And for the love of all that is good, do NOT install a factory 340 cam or any cam with a 114 LSA, which is nothing but a pressure bleeder to a 318.
End rant
Click to expand...


Bullshit
 
Hysteric said:
Depends on where you close the intake valve. As always run more comp.....
Click to expand...
CR would be nice but like a lot of these scenarios it's off the table, what cam is an acceptable compromise in this situation is the question?
 
AJ/FormS said:
Do you realize that with 3.21 gears, 26" tires, and an A904, your WOT mph is gonna be ~50 mph in First gear, and 84 in Second, both at 5500rpm@10% slip..
So, on the way to the speed limit, yur only gonna hit the powerpeak once.
And
On the 1-2 shift, the Rpm is gonna drop from 5500 to around 3250, which is waay off a 340 cam. which is not gonna wake up until IDK maybe 4000@ 60mph. Which means that from 50 to 60, your reduced-pressure-318 is gonna be a lil all talk/no action.
Almost everybody here will tell you that you won't notice it, but they're wrong. I mean the 340 cam will drop your cylinder pressure about 20psi, This will be most noticeable below 3000 rpm, but the softness carries right on up until the engine hits Peak-Efficiency and the power increase will pale in comparison to your expectations. So the reason you don't notice it because it is all soft, just less soft at rpm.
I mean everyone here will tell you that an 8/1 360-4v with a 340 cam, in 1974 DartSport, was a sucked out slug.
But those same people will tend to pump up the reputation of an 8/1 318-4v with the same cam, giving it glowing reports.
I swear there is no pleasing some of these clowns.

Do yourself a favor; the stock cam that is in your 67spec engine, is the right cam for those 3.21 gears. If you need a lil more oomph on take-off, just get a higher-stall convertor; at least a 2800, more if it's a city-only car.
And for the love of all that is good, do NOT install a factory 340 cam or any cam with a 114 LSA, which is nothing but a pressure bleeder to a 318.
End rant
Click to expand...
Ok you don't like the 340 cam which is fine there's a ton of options out there,
What about a comp cam xe250h with a 51* IVC or maybe grind stock one similar on a 108 if possible?

Does anyone even make a stock spec 340 cam anymore?
 
273 said:
CR would be nice but like a lot of these scenarios it's off the table, what cam is an acceptable compromise in this situation is the question?
Click to expand...
One that closes the intake valve at the right time to build enough cylinder pressure.
 
Hysteric said:
One that closes the intake valve at the right time to build enough cylinder pressure.
Click to expand...
And that is ? AJ say stock is 48* doubt you gonna get that with a decent bit more duration unless you go 107 lsa or tighter and or really advance the cam.
 
273 said:
And that is ? AJ say stock is 48* doubt you gonna get that with a decent bit more duration unless you go 107 lsa or tighter and or really advance the cam.
Click to expand...
Funny that.

Look at Cranes 260H
 
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