element303
Well-Known Member
Yeah thats the sound im looking for in idle but minus all that:
2 [2] Requires machining on cylinder heads.
7 [7] Stock springs cannot be used.
37 [37] Adjustable valve train required.
Thank you
is it worth installing cam in stock 318?
- Thread starter 68bb
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Yeah thats the sound im looking for in idle but minus all that:
2 [2] Requires machining on cylinder heads.
7 [7] Stock springs cannot be used.
37 [37] Adjustable valve train required.
Thank you
barnett468
Well-Known Member
Unfortunately you can't have your cake and eat it too . Any cam that is larger than stock will require different valve springs at the very least, however, a low budget option that does not require a spring change is to simply drill a lot of holes in your mufflers.
BlueDream
Aspiring Mopar enthusiast
I had that Thumpr cam in my 340 and it wasn't too bad performance wise, but it wasn't the best. Sounded great though! It still had some bite to back up that bark. COMP recommends their 995-16 springs (I think...goin' by memory here), which are a double spring. You can run that cam with a beefy single spring but it's not the best idea. When I talked to Comp about using the 901-16 with that cam they said it'd be fine down low but above 5,200 RPM or so, the valves might float. If you don't want to do the machining for double springs, you could probably find a suitable single spring. Also, it doesn't make a lot of vacuum so power brakes are iffy at best. Sounds great but it'd rob performance from your engine. I do NOT recommend this cam for your 318, and I'm speaking from experience here. I won't deny that it sounds wicked though.
Thumpr cam:
I ditched the Thumpr cam in favor of a COMP XE268h, which still sounds pretty good and is better for a street car. This cam uses a 901-16 spring which is a single spring that doesn't need any machine work to fit in the heads. It's a drop in replacement for the stock valve springs. More vacuum, broader powerband, and it's got a choppy but streetable idle. A lot of people have ran this cam in a 318 and it may or may not work well depending on the rest of your combo. There's a LOT to think about when picking out a cam.
XE268h Cam:
When I had a 318, I went with a COMP HE268h cam. It's milder than the XE268h but beefier than the stock cam. Vacuum brakes work well with this cam, and it idles nicely but with enough lumpiness so that people know it's not stock. 901-16 single springs are recommended, no machining required! Unless you are going to do more mods to the 318, you're going to want to keep the cam on the mild side. Wild cam in a stock 318 is the best way to make it gutless and miserable to drive.
318 w/HE268 Cam:
So yeah, if you want it to sound like a muscle car and still perform decently, go with a smaller cam. Something like the HE268 which is similar to a stock 340 cam. If you want a bigger cam, just know that you'll need to do supporting mods to go along with that cam.
Thumpr cam:
I ditched the Thumpr cam in favor of a COMP XE268h, which still sounds pretty good and is better for a street car. This cam uses a 901-16 spring which is a single spring that doesn't need any machine work to fit in the heads. It's a drop in replacement for the stock valve springs. More vacuum, broader powerband, and it's got a choppy but streetable idle. A lot of people have ran this cam in a 318 and it may or may not work well depending on the rest of your combo. There's a LOT to think about when picking out a cam.
XE268h Cam:
When I had a 318, I went with a COMP HE268h cam. It's milder than the XE268h but beefier than the stock cam. Vacuum brakes work well with this cam, and it idles nicely but with enough lumpiness so that people know it's not stock. 901-16 single springs are recommended, no machining required! Unless you are going to do more mods to the 318, you're going to want to keep the cam on the mild side. Wild cam in a stock 318 is the best way to make it gutless and miserable to drive.
318 w/HE268 Cam:
So yeah, if you want it to sound like a muscle car and still perform decently, go with a smaller cam. Something like the HE268 which is similar to a stock 340 cam. If you want a bigger cam, just know that you'll need to do supporting mods to go along with that cam.
element303
Well-Known Member
Spings are fine but I dont want to have to remove the heads. I dont want low budget or ghetto.
element303
Well-Known Member
Nice info thank you! The XE268h Cam sounds pretty good to me. But I guess the cam wont sound like thta unless I get rid of the stock header first. It sounds like its completely restricted.
67Dart273
Well-Known Member
The question you have to ask yourself, is "do I want to sound manly" or do I ACTUALLY want some performance? The LAST thing you need on a stock/ fairly stock engine (318) is headers and a huge cam
1....If you don't have duals get dual exhaust. if you have a stock single in good shape, you can have the "Y" pipe cut and the other pipe run
2....Recurve the ignition, regardless of the cam used
3....Put a good little 4 bbl carb on it and a good intake. Don't go 'too big' and use an intake, such as a stock 340/360 intake, or an Edlebrock Performer / Performer RPM
4....Cam.. Do NOT go too big, and forget this bullshit of "manly sound" Put something like a factory 340 (equivalent) cam in the thing, and properly degree it in.
element303
Well-Known Member
Its about sound. All Im looking for is that rough idle for now. If I want real performance I get a turbo kit, but then again I would need to convert it to standard first. This one is just for cruising. Although I have to say it pulls pretty good. I would almost say its faster than my '84 Z28 350.
BlueDream
Aspiring Mopar enthusiast
In that case, start pulling plug wires until the engine won't run anymore. Then replace the last wire you pulled. Now your engine idles rough and you can see what the off-idle torque would be like with a cam that's too big for your engine.
Use the Thumper cam for the rhythm and the muffler of your choice for sound.
Get the spring specs of the Thumper cam since someone said (though I do not know) that the springs need head work to install and use.
Switch to similar Crane springs with the correct inside diameter to clear.
On my old build, I choose a Crane cam and there springs are a direct fit. BUT he sure to choose correctly!
Oh! The 318 can and will outrun a lot of Chevy 350's. Build wisely for such endevores. Make sure the car is light!
Get the spring specs of the Thumper cam since someone said (though I do not know) that the springs need head work to install and use.
Switch to similar Crane springs with the correct inside diameter to clear.
On my old build, I choose a Crane cam and there springs are a direct fit. BUT he sure to choose correctly!
Oh! The 318 can and will outrun a lot of Chevy 350's. Build wisely for such endevores. Make sure the car is light!
And that's the beauty of (this) forum(s) and searching. There is a lot here to dig through.
67Dart273
Well-Known Member
Do what you want. Some things never change. I'm 68 this year. Kids were doing this in NINETEEN sixty eight when I was 20. I'm sure they were doing it in 1958, I just didn't quite notice
element303
Well-Known Member
That sounds good to me and worth to research. Now I know a direction. Thank you guys.
barnett468
Well-Known Member
ok, that cam i posted is your cam.
nm9stheham
Well-Known Member
Well, it started in 2010, but post #21 is a new inquiry on this theme.
For element303: If you want a lumpy idle, be aware that you will dump some fuel mileage. Going with the Hughes Whiplash will give the idle, but the 107 lobe separation angle that creates the lumpy sounds is what will also lower fuel mileage.
If you can accept that, then I personally would go with the Whiplash (though I never go for a 'sound' as a goal; a well built engine will have a good sound as a byproduct). At least you get some good lift to help cylinder filling at lower RPM's; that will make better torque. You surely need better valve springs and ones that will accept the higher lift without binding. Make sure you properly time your new cam!
And lot of the sound in the video that you linked comes from a much more open exhaust. You're not going to get that exact sound without a lot more than a simple cam change.
For element303: If you want a lumpy idle, be aware that you will dump some fuel mileage. Going with the Hughes Whiplash will give the idle, but the 107 lobe separation angle that creates the lumpy sounds is what will also lower fuel mileage.
If you can accept that, then I personally would go with the Whiplash (though I never go for a 'sound' as a goal; a well built engine will have a good sound as a byproduct). At least you get some good lift to help cylinder filling at lower RPM's; that will make better torque. You surely need better valve springs and ones that will accept the higher lift without binding. Make sure you properly time your new cam!
And lot of the sound in the video that you linked comes from a much more open exhaust. You're not going to get that exact sound without a lot more than a simple cam change.
element303
Well-Known Member
I was testing a little around with the exhaust and had it off at one point for some work on the bottom and turned it on out of curiosity without exhaust, but it sounded pretty lame. I can only guess its the stock header restricting the flow. I would like to get cams that are not too extreme and that work with stock head and parts but if thats not possible I will take some money for that aside and do something right.
ir3333
Well-Known Member
..i don't think a cam itself would increase a stock 318 by 50 hp.
but a cam,intake,4bbl and duals or headers should give 35 - 40 hp.
but a cam,intake,4bbl and duals or headers should give 35 - 40 hp.
element303
Well-Known Member
I agree.
BlueDream
Aspiring Mopar enthusiast
What rear gears do you have? What's your final goal for the car as a whole?
It's fine to want a cam that sounds good but if you're going to spend the money doing the upgrade, you might as well plan for the future. It's worth noting that what sounds mild in a 340 or 360 will sound rougher in a 318. I really wouldn't go any bigger than an XE268h on a mild 318, and even that is pushing it. With the right supporting mods, the cam will perform decently and sound awesome. Swapping springs is easy and can be done with the heads on. You'll also want to check pushrod length and lifter preload with the new cam.
I know you mainly want the sound, but if you can get something that performs better AND has the sound you're looking for; it's a win-win. Going fast AND sounding good is a lot more fun than sounding like a top fuel dragster but being slower than a V6 Mustang.
It's fine to want a cam that sounds good but if you're going to spend the money doing the upgrade, you might as well plan for the future. It's worth noting that what sounds mild in a 340 or 360 will sound rougher in a 318. I really wouldn't go any bigger than an XE268h on a mild 318, and even that is pushing it. With the right supporting mods, the cam will perform decently and sound awesome. Swapping springs is easy and can be done with the heads on. You'll also want to check pushrod length and lifter preload with the new cam.
I know you mainly want the sound, but if you can get something that performs better AND has the sound you're looking for; it's a win-win. Going fast AND sounding good is a lot more fun than sounding like a top fuel dragster but being slower than a V6 Mustang.
element303
Well-Known Member
Well, I was lucky enough to get the car in factory setup with everything still in the car all the way to working A/C and reserve tire still in the trunk. I guess its just for cruising when I finished the body and paint more than performance, because lets be honest. A 318 without turbo isnt gonna be anything impressive so if I would one day want pure performance, I would try to get a big block or at least the 340 engine with 4 speed stick that the guy I bought it from have as well. I just find the car too soft when its idling or on throttle. It sounds very healthy as it was meant to sound I guess, but I like to hear some more of those 5,2 liters, thats all.
With other words, I just want it to sound more "muscle".
With other words, I just want it to sound more "muscle".
nm9stheham
Well-Known Member
It is the stock exhaust manifold AND the cam.... and the lower stock compression.
The advantage of going with headers and a good exhaust is that it will help all across the RPM range. It will help with torque, power, and with mileage. IMHO you are on the right track with the cam type:
- Keep the duration low to maintain low/mid RPM torque
- Keep the lift high to help cylinder filling and lower end torque
- Look at LSA to either help mileage and lower end torque (wider LSA) or help top end power (narrower LSA)
- Cam advance helps low end torque; many cams have this ground in. (Example: If LSA is 112 and ICL is 108, then the cam has 4 degrees of ground-in advance.) More advacne helps lower end torque.
If you notice, I keep mentioning lower end torque. This is for all-around street manners. 318's are lower compression and suffer quickly from loss of low end torque if too wild a cam is used.
If you are looking for lowest drag race ET's, then a different philosophy for cam choice is suitable. Let us know what the main use(s) of the car will be.
Long term thinking, breathing in the head will only help high RPM power, and the low end torque can be managed with the cam choice.
element303
Well-Known Member
Interesting. The previous owner told me that I have the 318 engine but a high compression version they built. Could that be right? I have not seen any info about 2 versions of this engine.
Just cruising around few days a month. No drag racing or anything.
nm9stheham
Well-Known Member
Well, I am assuming that you have the earlier, non-Magnum 318 (the 'LA' version). There was the car engine, with a real static CR in the low 8's and then the truck 318 with SCR in the 7's, but neither is high compression. The Magnum 318 (5.2L) was a higher compression, in the upper 8's IIRC, but that is not HIGH compression really. So the PO was.... let us say.... 'misinformed'.
If you are cruising around, then by all means, you have to pay attention to low end torque. Low end torque and wide torque band make cruising 'workable'; you have 'go' anytime you push on the go pedal, not a bog waiting for the RPM's to build until some torque begins to happen. So your focus on a mild cam is suitable. Take some time a look up so called 'torque' cams and the smaller duration cams like Lunati Voodoo's and such. They all will be shorter in duration, and the ones I like best will be as high as possible in lift. Then pay attention to the LSA.
The on thing to be careful of with a short duration, very high lift cam like the Whiplash is to make sure that that valve train can take it. Stock valve springs will bind, or be to close to spring bind, with that amount lift and will allow the valve to float at higher RPM's. So you surely need a cam kit with springs. And, you need to be sure that the valve retainers do not hit the valve stem seals and valve guides with higher lifts. That is one reason that sticking with a lift in the range of .450-.460" works well; it is safer for things like retainer clearance. A lot to think about!
If you are cruising around, then by all means, you have to pay attention to low end torque. Low end torque and wide torque band make cruising 'workable'; you have 'go' anytime you push on the go pedal, not a bog waiting for the RPM's to build until some torque begins to happen. So your focus on a mild cam is suitable. Take some time a look up so called 'torque' cams and the smaller duration cams like Lunati Voodoo's and such. They all will be shorter in duration, and the ones I like best will be as high as possible in lift. Then pay attention to the LSA.
The on thing to be careful of with a short duration, very high lift cam like the Whiplash is to make sure that that valve train can take it. Stock valve springs will bind, or be to close to spring bind, with that amount lift and will allow the valve to float at higher RPM's. So you surely need a cam kit with springs. And, you need to be sure that the valve retainers do not hit the valve stem seals and valve guides with higher lifts. That is one reason that sticking with a lift in the range of .450-.460" works well; it is safer for things like retainer clearance. A lot to think about!
element303
Well-Known Member
Very very interesting. Thank you guys for taking the time to write so much detailed information. I will look into it all. I will have 2-3 months to go with the body then I start getting mechanical parts.
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