1.6 rockers with stock 318 cam??

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Salty Dog said:
Dear sir, please re-check your post, duration @ 050 reading 390 wuold be larger than this race cam listed below;

http://www.summitracing.com/parts/LUN-504A4LUN/

Something is a miss here. It aint me!

Lift, yes, I agree. Duration, ... NO. That cam he liosted is a small lazy cam.
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Your correct. A mis-type on my part. I meant 390 total duration. Yes the cam he listed is a lazy cam. IMO a Lunati 60400 or Comp Xe256 or something similar would be much better for him. Of course he'd also have to change the valve springs if he changed the cam.
 
Salty Dog said:
LOL-ROFLMAO

OK, believe what you think, it's OK, I'm so glad I could give away some of my 30+ years of working on making engines go fast and such.

Have at it and fun. Almost nice talking to ya.
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For the love of Pete, you confounded man! Were do you get you info from? Honestly, I'd like to know. What do you really think a stock 318 cam has for duration, at .050" or otherwise?

BTW I really like the Cuda in your avatar....or I suppose you're going to tell me it's a Challenger. lol
 
1.6 rocker's on exhaust side only might improve exhaust scavenging and gas mileage?
 
'teen machine said:
BTW I really like the Cuda in your avatar....or I suppose you're going to tell me it's a Challenger. lol
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Thank you, it is a Cuda.

I'm just trying to help on the cam, sorry about the last post. Sorry to waste your time and make you angry.

Read up on cams, read everything you can get your hands on.
 
Salty Dog said:
Thank you, it is a Cuda.

I'm just trying to help on the cam, sorry about the last post. Sorry to waste your time and make you angry.

Read up on cams, read everything you can get your hands on.
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I know you're trying to help. I'm sorry I've been making it hard for you, and wasting your time.

I have read allot on cams, not as much as there is out there to read and I don't have 30+ years experience with them.

I think I'll just stick with my stock cam for now and upgrade the intake and put on a set of long tube headers.

On a stock 318 cam the lobe would obviously be shorter, but would the ramp rate be comparable to a good cam that you mentioned? Or do they have a gradual ramp rate instead of steep?

Also I'm thinking of re curving the advance on my timing(electronic ignition)....Any suggestions?
 
I'm not aware of there ramp rate. A cam upgrade even with the Chevy lobe used would be a noticeable power difference. IMO, do the cam, lifter and spring upgrade at the same time you do the intake, carb and headers. As far as ignition goes, the OE electronic w/ a Chrome box is the bet OE style ignition you can do. Though, a MSD will net you what they claim, easier starts, more power and mileage. I have the OE hooked up and left behind should the MSD fail to work.
 
Just to back up what others have said about the rocker arm ratio change. The stock 318 cam has .373"/.399" lift. Changing to 1.6 rockers will result in .397"/.425" lift. I just recently tested a 318 head with some bowl work that flowed 155.8 cfm at .300" lift, 168.7 cfm @ .400" lift and 169.9 cfm @ .500" lift. A switch from 1.5 to 1.6 rockers would result in no perceptable performance benefit with the stock cam and heads.

As to stock cam duration. The stock 340 camshaft is 268/276 advertised and 208/214 @ .050".

I don't have the duration at .050" for the 318 camshaft, but the advertised duration is 240/248. If the 318 cam used only 50 degrees rather than the 60 degrees the 340 cam uses to get the .050" duration, the 318 cam would still have only 190/198 degrees. Seems to be a fairly mild camshaft.

But......

Unless you have tested the duration of the aftermarket cam and the stock cam, at the same starting (advertised) and .050" lifts, you cannot accurately tell the difference between the aftermarket cam and the stock cam.
 
IQ52 said:
I just recently tested a 318 head with some bowl work that flowed 155.8 cfm at .300" lift, 168.7 cfm @ .400" lift and 169.9 cfm @ .500" lift.
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How much bowl work?

was that after a valve job?

I think the factory valve job and seat depth was pretty good, better than most average shops.imo
 
Not much bowl work as we got another, untouched port, at 50.7 @ .100", 108.9 @ .200" 160.5 @ .300", 171.6 @ .400 and 171.6 @ .500".

The flows for the slightly worked port were, 69.7 @ .100", 117.7 @ .200", 155.8 @ .300" 168.7 @ .400 and 169.9 @ .500". Valve job but nothing fancy.

The nice port from 2 years ago, with a roughed in valve job on the 318 head, shows what a 675 head can really do.

79.6 @ .100"
138.1 @ .200"
188.8 @ .300"
230.0 @ .400"
266.0 @ .500"
270.8 @ .540".

Pretty sure there is even more flow available, but haven't had the inclination to test the head more.
 
IQ52 said:
Not much bowl work as we got another, untouched port, at 50.7 @ .100", 108.9 @ .200" 160.5 @ .300", 171.6 @ .400 and 171.6 @ .500".

The flows for the slightly worked port were, 69.7 @ .100", 117.7 @ .200", 155.8 @ .300" 168.7 @ .400 and 169.9 @ .500". Valve job but nothing fancy.

The nice port from 2 years ago, with a roughed in valve job on the 318 head, shows what a 675 head can really do.

79.6 @ .100"
138.1 @ .200"
188.8 @ .300"
230.0 @ .400"
266.0 @ .500"
270.8 @ .540".

Pretty sure there is even more flow available, but haven't had the inclination to test the head more.
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whoa doggy!! not with stock valve diameter?
what size valve?
360 port window?
 
Right, not with the stock valve diameter. The only reasons to keep the stock valve diameter would be if you had to run the 675 on a 273 or you couldn't afford larger valves. Both very good reasons by the way.
 
IQ52 said:
Right, not with the stock valve diameter. The only reasons to keep the stock valve diameter would be if you had to run the 675 on a 273 or you couldn't afford larger valves. Both very good reasons by the way.
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Yes indeed.

I remember telling somebody about 250-270cfm out of a 675, they just laughed...:happy1:

That short turn with the mondo valve diameter will damn near blend/lay back to the push rod pinch with the way the floor is....and that roof is mighty thick too ;)
 
1wild&crazyguy said:
Yes indeed.

I remember telling somebody about 250-270cfm out of a 675, they just laughed...:happy1:

That short turn with the mondo valve diameter will damn near blend/lay back to the push rod pinch with the way the floor is....and that roof is mighty thick too ;)
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And this type of flow is possible with a 1.88/1.60 valve arrangement?
This is considered a full port job?
 
Salty Dog said:
And this type of flow is possible with a 1.88/1.60 valve arrangement?
This is considered a full port job?
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You should ask IQ52, for those numbers it just makes sense to use something at 2'' or bigger...i would think much diff between the 1.78 and 1.88....its just +.050

Is this a maxed out version? IMO yes.

The runner is just smaller cast inside, the outside parameter is almost like a 360. same push rod location, divider wall, just more to grind out 'except the guide'. The main difference is the guide, floor, ssr.

318 port floors are flatter.

take a 340 and put a set heads on like IQ52's in his example...then snap the throttle and tell us what u think....that is if the port is still smaller..lol

I will do a thread with 2.02's put into the 675's i have in the thread and report back.
Thing to remember is that a ported 340/360 head has better low lift numbers still...so where do you really end up better?

btw, IQ52..what port volume do you end up with?
 
moturbopar said:
These are the specs for the 318 2 bbl cam out of my barracuda. if anyone is still interested in the 318 cam specs.

int duration at .050 is 180
ext .050 192
int lift .372
ext .399
109 lobe seperation

Anyways this would be the cam i would run.

http://www.summitracing.com/parts/HRS-711381-10/
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That cam has some good looking specs for a low compression small engine but the only problem may be the lift. At .494" lift your really pushing the limits of a stock head. I've seen stock heads slap the spring retainer at .450 lift. Most will go .465~.475" but you always have to check them.
 
The new howards cams are crazy. I really like them. I should have said if he planned on doing some head/machine work that this would be a good cam. Stock springs and stuff wont work with this cam.
 
1wild&crazyguy said:
You should ask IQ52, for those numbers it just makes sense to use something at 2'' or bigger...i would think much diff between the 1.78 and 1.88....its just +.050

Is this a maxed out version? IMO yes.

The runner is just smaller cast inside, the outside parameter is almost like a 360. same push rod location, divider wall, just more to grind out 'except the guide'. The main difference is the guide, floor, ssr.

318 port floors are flatter.

take a 340 and put a set heads on like IQ52's in his example...then snap the throttle and tell us what u think....that is if the port is still smaller..lol

I will do a thread with 2.02's put into the 675's i have in the thread and report back.
Thing to remember is that a ported 340/360 head has better low lift numbers still...so where do you really end up better?

btw, IQ52..what port volume do you end up with?
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Sorry about being so late in reply 1w&cg.

Been real busy in the shop lately. Yes the valves in the 675 were larger than 2.00". As to port volume, never measured, never curious enough. I don't think you can get the port volume too large or a valve too big in that head to slow down a 318.
 
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