Yet Another Cam Choice/ Engine Combo Thread For 318

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64 SRT8 Dart

64 SRT8 Dart

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After reading some of the other threads about cam choices, etc and seeing all the talk about static compression and what cam should one need to help bleed off compression to prevent pre-det, I'm now questioning the cam I have for my 318 and can use a little advice. :)

Engine is 318 bored .030 honed with torque plate.
Align honed (due to no.3 main being spun).
Decked to zero to Fed Mog/Sterling Z285NP Cast Flat tops.
ARP main studs w/windage tray.
Rods rebushed, resized, ARP bolts
Cast crank turned .010 rods/ .030 mains, straightened.
Rot. assembly balanced.

Heads are smog 318 "973's" w/1.78" intake valve that are gasket matched and have a mild port job on both int and ex. I'm gonna say that chambers are stock cc so around 62cc I guess.
273 Adjustable Rockers.
Intake is a Performer 318/360.
Carb will be a Holley 650DP Spread bore w/1" spacer.
Exhaust is Hooker SuperComp 5208's.

Well if I use Summit's compression calc, it puts my compression at just below 10:1 with a .040 head gasket.
The cam I have now is the Crane Energizer .454/.454 216/216 @.050.
I live at around 6000ft above sea level if this helps.

I do have a set of 1.88" J heads but they would need $$$ work as in hardened seats, all new valves, etc. The 1.78" heads I have now already have hardened seats, new seals, good valves so that's why I plan on using them. Not to mention reading about port velocity, etc, etc.

Will be going in my 66 Valiant w/built 904 and planned on getting a converter with around 2000rpm stall if using this cam.

Will this cam be too small for the compression this engine will make??
 
First cc the heads so you know the real compression ratio.

Second thing is u live at 6000 ft, so you can bump the compression a lot higher than sea level guys on pump gas, so I would figure that into your calculation.

Third is the cam is ,while not bad, ancient and not that great of a choice.imo

I would use the comp.268 or solid lifter equivelant.

Btw stock convertors typically flash around 1800rpm, so if you are gonna spend money there...make it count and shoot for about 2500 rpm. Even if the cam u use bands from 2000...u are better off stalling a lil higher into the torque curve.
 
Make sure those 1975/1976 #3769973 Cylinder Heads are CC'd.

Though it states that they came through within a range of 63.0 to 69.0 cc's
in the open combustion chamber, many left the factory with the higher cc's.
I've CC'd several that were close to '68.0'.

The standard formula of milling comes to;
* .0053" per 1 CC (Mopar Small Block Open Chamber Cylinder Head)

The factory listed (cc) would be 63.0 to equate to 9.1 to 1 Compression -

Note; Since you brought the piston deck height to .000 - by milling .056 of the block deck (approximate),
it looks like you eliminated (10.50 cc's) from the cylinder bore.

The Compression Ratio with a stock (63.0 CC Chamber) should be right on 10.00 Compression with
an .030 Thickness Head Gasket

The Compression Ratio with an .040 Thickness Head Gasket should be at 9.83

Though a 'step up' in Camshaft would be a gain in performance, the Crane Energizer Camshaft
is not bad, as stated in the previous post, and is near similar to the Compu-Cam #268.
.454/.454 Lift
.268/268 Duration
.218/218 @ .050 Lift
110* Lobe Separation
106* Intake Centerline

With the Automatic, I like that mid-range Camshaft.
 
Thanks guys!! I wonder how much leeway I have for compression being at this elevation? Maybe a point?

I filled out the cam/car/engine info on Lunati's site and they recommended cam 1020052. Lift is .465/.465 with dur @.050 as 228/235. 110/106 2400-5800.
They recommend a 2500 stall, 9.5:1 comp, headers, and at least a 3.5:1 gear or num higher.
Anyone use this cam before? I kinda like the numbers and might give it a try.
 
Posts 2 and 3,great info.The answer to your question: What do you want it to do,and what do you considetr affordable/driveable. You have a really nice combo on tap BTW. As for compression,see Moped kid 3 ,run 10 to 1,on Magnum heads,215/223@ .050 cam.
 
Thanks for the compliment Mr. A-Body -

Lunati Street/Strip (Hydraulic) #10020052
Lift............................465/.465
Duration.....................285*/305*
Duration @ .050 ..........228*/235*
Lobe Separation...........110*
Intake centeline...........106*

Performance Range.......2400 - 5800 RPM
Lopey Idle

Cost $194

* This camshaft works very well with a 318 Mopar Small-Block, 10.0-1 Compression, and with small-valve Cylinder Heads.
* A perfect fit for the Street Performance 318, with Headers, Intake and Carburetor upgrade.
* An excellent all-around performer, with good mid-range pull.
* Works very well with 3.91 Gears
* Automatic Transmission Cars should utilize a 2200 RPM Stall Converter for optimal performance.

SRT,
1) What gears are you using ?
2) The rocker arms - are they stock, or steel roller type.
3) Valve Spring Pressure ?
 
A body- car will be a driver but will see as much track time as I can so I'm not too worried about a lumpy idle or gas mileage.

69- I'm not too sure about the gears yet. The tag is missing off the diff so I need to pull the cover and have a looksee. It's an original slant car is I'm guessing it's around 3.23s or so. Rockers are 273 adjustables and I'll get whatever spring to match the cam.
 
SRT 8,

For fun, we just found a set of #3769773 Cylinder Heads. Checked out the Combustion Chamber cc's on an untouched stock head.....

CC'd at 68.1

The specs state, that a 1976 318 with a negative (-.056) below deck piston height,
#3769973 Cylinder Heads with 63.0 cc's and a .030 Head Gasket.

Compression Ratio = 9.10
 
Thanks 69, Hmmmm, I 'll have the engine shop cc the heads when they do the valve job, etc and I guess go from there.
As far as head gasket I'm prob gonna use either the Felpro permatorque which i think is around .039 compressed or the Mr. Gasket MLS which are at .040 compressed. I'm also at zero deck.
 
Srt,

Good Job.

318 with 'Zero' Deck Height
Cylinder Heads with (63 cc) 'Open Chamber' Combustion Chambers
.040 Fel-Pro Perma-Torque Head Gasket

Compression Ratio = 9.83
 
Abodybomber said:
Posts 2 and 3,great info.The answer to your question: What do you want it to do,and what do you considetr affordable/driveable. You have a really nice combo on tap BTW. As for compression,see Moped kid 3 ,run 10 to 1,on Magnum heads,215/223@ .050 cam.
Click to expand...

Hey 64 SRT8 Dart yeah I live in Denver and I built an LA 360 with Magnum heads and 10.42 compression, and the smallest Lunati Voodoo cam in the line (previous part #60401). It is on the edge of running detonation-free pump gas in warm weather for sure, if I get into the secondaries when it's sunny and 60*+ outside I get some pinging if I'm using mid-grade (87 for us). With the small cam my dynamic compression is up there, I am looking to swap to a bigger cam sometime. Another member 'moper' advises 8.75:1 max dynamic compression for closed-chamber heads (mine is like 8.72) and 8.25:1 for open chamber heads I believe. Just look up a calculator on the web that accounts for elevation and try some numbers from various cams to get you around 8-8.25 dynamic compression. If what 69 Cuda 440 says is true then you'll want a cam with 40-50* ADC intake closing.

BTW I used to live in Monument and have friends who live in the Springs
 
If you are at zero deck with those pistons, the block must have been cut a fair amount. This means 2 things: First, custom shorter pushrods. The adjustment screws on the rockers may not be able to compensate. Second, it doesn't matter if you remove material form the deck surface of the heads or the block, it affects intake manifold fitment the same. So, you can either cut the port face of the heads (preferred, although the heads will now be "matched" to the block, intake manifolds can be swapped readily) or you can remove material from the port faces of the intake (more difficult for future intake swaps, any intake will have to be cut, and will probably not work on other engines hurting resale value).

That cam is really about max for the small port heads. It will work fine with small heads, but it will work better with big port heads. If it's mostly a strip car, why bother with the small port heads?

Double pumper + small dual plane intake + 1" (open hole?) spacer?!?
 
One of our customers is using this Camshaft with his Street Tweaked 318, and
is running around 9.75-1 Compression in the Mountains of Vermont.

Compu-Cam 'Extreme-Energy XE-268H'
Part #20-223-3

Good Performer from {1600 to 5800 RPM's}

Lift...................... .477/.480
Duration................ 268*/280*
Duration @ .050 ..... 224"/230*
Lobe Lift............... .318/.320
Lobe Separation...... 110*
Intake Centerline..... 106"
Exhaust................. 26* Closed ATDC / 74* Open BBDC
Intake................... 28* Open BTDC / 60* Closed ABDC

He is still using his 'Stock Torque Converter', and runs with 3.91 Gears.

The car is quite responsive, and pulls strong and steady at all RPM Levels right up to 5200 RPM

Torque is strong and consistent right from the 'Get-Go'.

If you're staying with the Stock Converter due to 'budget restrictions', this would be the optimal
Camshaft to go with, and with #901-16 Valve Springs, Single-Coil w/Damper.
#101 lbs. @ 1.650"
#242 lbs. @ 1.250"

With 3.91 Gears, a 'perfect driveable' Street/Strip Combination
 
you are definitely going to have to run super unleaded. if you think you have too much compression, and you have detonation problems... you could run E85 with a quickfuel E85 carb.

however, it's not available everywhere. then you will be stuck running race fuel.

i wouldnt have the heads milled even more! you are already pushing the limits. iron heads are not forgiving like aluminum heads as far as heat dissipation to prefent detonation. all the cam overlap in the world is not going to save you if you go too far.

there are static and dynamic compression ratio calculators here:
http://www.kb-silvolite.com/calc.php

you need a lot more info to do the dynamic calculation.

Cylinder head volume (cc)
Piston head volume (cc)
gasket thickness (in)
gasket bore (in)
Deck Clearance (probably zero in.)
Stroke (inches)
Rod Length (inches)
Intake Closing Point (Degrees)ABDC @ 0.050 lift +15 degrees
 
C130 Chief: The car is mostly a driver and will see the track a few times a year. The 1" spacer will be a 4-hole. I've used this engine combo w/the crane cam in a low compression(8:1)/ stock rocker/ stock headed 318 in a 71 Dart before and it ran 13.90'a in St. Louis in 2001.

Now I'll have around 9.5-10:1 comp and the heads have been opened up, but using stock valves and also have the adjustable rockers. Yes, I know about having to mill the heads or intake and custom pushrods because so much has been taken off the deck.(Which I'm kinda frustrated about, lol) As far as carb, I might be fine with a 600 Vac Sec??

69, as far as converter, if I can find a decent one in the 2000-2500 range for a decent price I may be able to open the pocket book more...keeping in mind it is a 904. Wish I had my 8 3/4 cut down cuz I have two 489 3rd members, one with 3.55's and one with 3.91's. lol

moparlover, thanks for the info and I'm sure I'm gonna be good with at least mid-grade. Hopefully, lol
 
SRT8,

Sounds like you know what your doing,

On the budget end, I would go with the Compu-Cam 'XE-268H' Cam and Kit set-up,
stay with the Stock Converter, and go with 3.91 Gears.

Then save the money for a better set of Cylinder Head's. Those #3769973 are
functional for 'Street Use', but have limited intake flow compared to other
Mopar Small Block Cylinder Heads.

You've got a good Edelbrock Performer Intake and Holley '650-DP', and you need
some improved breathing to unleash the 'Mid-Range' power in that LA-318.

A set of 318 (#4323302 High-Swirl) Cylinder Heads would be the next best 'low-cost'
investement. High-Velocity ports, and good flow with just a little bit of work (Bowl-blending
and Gasket-port matching). The 'high-swirl' combustion chamber helps prevent detonation.
Of course installing bigger valves (1.88" Intake and 1.60" Exhaust), would be optimal,
but not completely neccessary for a Street Runner.

The #302 Cylinder Heads are usually found with a 62.0 to 65.0 CC Combsution Chamber,
so it gives you some room to mill them, and they work great with a '318' that has
between 9.5 and 10.0 Compression-Ratio. And they have 'hardened valve seats'. With
some port work, they deliver good low-end torque, and are responsive.

And eventually 'Stainless-steel Roller Rocker-arms.

mopar318-1.jpg
 
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