What size cam should I use?

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RedScampi

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I have a bone stock 318, 1968 block, runs great but idles smooth and stock-like. My question is what is the biggest cam I can use without modifying the valve train? I want the motor to sound more aggressive even if it isn't. If you can recommend a brand and part number that would be great too.
 
Springs should be purchased along with the cam. MoPar springs require no mods to the head what - so - ever while Comp Cams springs do. You can match up the pressures of a Mopar spring to a Comp (Or other) spring if you look for there rates.

A cam that has a "Chop" to it's idle are ground on a tighter centerline or a lower number. 110 is most popular. Higher compression adds pop! to the sound, just a FYI note.

The biggest cam you can install without modifying is not the issue but the biggest cam that is sanely good to use in the car is another issue. Also, as well as not changing anything else like a gear ratio or torque converter.

If all is left stock and assumed is a Hwy. gear ratio, a cam with a 218 intake is as high as I wold go.
 
I have a Comp cam in my 318. It is part #20-232-4 It gives a nice cam sound and delivers good response. It is a 280/480. Intake and exhaust is 230 at .050. Lobe lift .3200, lobe separation is 110. You will need to watch the springs as suggested by Rumblefish. I didn't and I quickly learned about coil bind, bent pushrods and valves. It also sucked a valve and did quite alot of damage. Use the recommended CC valve springs 901-16 and PLEASE check for coil bind.
 
I put a Lunati Voodoo 256/262 in my stock-compression 318 with stock reman'd 302 heads and even with the secondaries on the ThermoQuad disconnected, a stock-level advance curve in the dizzy, stock single exhaust, and 2.76:1 gears it pulls at least as hard on the low-end as it did with the stock cam and 2-bbl. I can also feel it start to pull harder around 2500-3000 RPM so it should haul *** once I get the secondaries dialed in and a nice dual exhaust on there. Not to mention even with the bone-stock exhaust the idle sound went from a soft "chuff-chuff" to a very deep, constant "burble". Of course I am at 7000 ft. above sea level and the rings/cylinders aren't in perfect shape so it pulls only 11-12" of idle vacuum in gear (around 600-700 RPM). That's only a little less than when it was stock though so you shouldn't see any reduction in idle quality at all.

BTW that cam's got intake lift of .454" and exhaust .475" and I used Comp 901 springs. No coil bind with stock heads and valve locks. Just make sure you use the correct aftermarket retainers.
 
If I may I just put the 280 480 cam in my 318 I plan on useing the stock 318heads what springs should I use the 901 and anything else should I get from Comp cams i sure dont want problims now.This cam will go in my 360 next winter.Thanks.
 
RedScampi said:
I have a bone stock 318, 1968 block, runs great but idles smooth and stock-like. My question is what is the biggest cam I can use without modifying the valve train? I want the motor to sound more aggressive even if it isn't. If you can recommend a brand and part number that would be great too.
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Comp makes thumpr cams, just for people like you.

Me?

Nothings more sad than a mean sounding car that don't go.
 
Snake said:
If I may I just put the 280 480 cam in my 318 I plan on useing the stock 318heads what springs should I use the 901 and anything else should I get from Comp cams i sure dont want problims now.This cam will go in my 360 next winter.Thanks.
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A 280/.480 cam from what manufacture? Comp?

Get the whole comp set up. They have matched parts so theres no guess work and posts like this will not be needed because Comp did all the work for you.
 
The 280 grind Comp is an oldie. You can do better now. I've used the XE262 with good results. It's modern, Lunati has their similar VooDoo lineup. At any rate, keep the cam size moderate and then you can use the single spring for them.
 
Comp has a line of cams called Thumpa that are designed to give you a lumpy idle without the down side of putting in a big cam that kills your bottom end. I would take a look at these, one of the smaller ones would likely be your best bet.
 
dodgetkboy78 said:
yeah, they OK.........

Buuuuuttttt.

A POWERFUL motor sounds better.
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Yes, very true. I'd love to do that but are YOU going to pay for it? I have two kids in college, a mortgage and I'm trying to save for retirement. If I do what you are suggesting I will have to live in my car when it's done. Power = $. No two ways about it. I have a great running 318 now. Should I throw it away and build a 340 or even a 440? I don't mean to be cynical but so many people make posts that are unhelpful like, "your motor is crap, get a big block!" without any idea of how much money they are talking about. Some of us live in the real world.
Thank you to everyone for the ideas, I'll be getting a cam in a couple of weeks.
 
If you are on a budget, check Summit brand cams. Usually less than $100/kit
Valve springs..... MP 249's..

Bob
 
RedScampi said:
Yes, very true. I'd love to do that but are YOU going to pay for it? I have two kids in college, a mortgage and I'm trying to save for retirement. If I do what you are suggesting I will have to live in my car when it's done. Power = $. No two ways about it. I have a great running 318 now. Should I throw it away and build a 340 or even a 440? I don't mean to be cynical but so many people make posts that are unhelpful like, "your motor is crap, get a big block!" without any idea of how much money they are talking about. Some of us live in the real world.
Thank you to everyone for the ideas, I'll be getting a cam in a couple of weeks.
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Did I say throw money away, throw your engine away, or your motor is crap?

No.

You can get power easy out of a 318, even with a cam change. But choosing a cam, for "SOund" may just leave you with a dog.

Go for a milder cam, please. You will have power with it. (I have heard 13 sec cars idle so smooth you would think it is stock. RB's of course, but building power is the way to go.)

A comp 260/260 sounds great with duals and headers.
The 340 cam, sounds great.
I can get a clip of a 360 with the cheapo Summit 270/280 cam if you would like to hear it. (Right out the door)
Also have a clip of a 260 comp in a 2bbl 318, and the 268/276 Voodoo. (Lunati's version of the 340 cam)

All I am saying, is go after performance, and it will sound good.
 
Ok, i apologize for the cranky tone of my posts. I have had to put up with a lot of unsolicited advice from several people in the last few days and my tolerance level is low. I'm sorry for misinterpreting your posts. I guess my original post was ill considered. i should have asked, "What's the best cam for performance that also gives a decent sound that will work with a stock motor?". I also neglected to mention that the motor is not completely stock, just the internals. It also has an Edelbrock Performer intake, Pertronix ignition and Doug's headers on it.
 
I have the small voodoo 60401 in my 318 and love it. just enought lope so its nothing crazy, makes great power, and it will work with stock internals.
 
Here what I used in my 1983 Plymouth cop car 318 4bbl . It gave the motor a nice deep rumbly sound,kinda like a 60's era cop car might have ha

Isky supercam .435 lift,262 duration. and 108 centreline.

Even though the cop cars compression is low it helps it quite a bit.
 
RedScampi said:
Ok, i apologize for the cranky tone of my posts. I have had to put up with a lot of unsolicited advice from several people in the last few days and my tolerance level is low. I'm sorry for misinterpreting your posts. I guess my original post was ill considered. i should have asked, "What's the best cam for performance that also gives a decent sound that will work with a stock motor?". I also neglected to mention that the motor is not completely stock, just the internals. It also has an Edelbrock Performer intake, Pertronix ignition and Doug's headers on it.
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No apology needed. Just don't want you to choose some radical cam and have it die when you put it in gear.

That ISKY cam will make a good fit.
 
OK, after reading a bewildering array of input, what are your opinions on this specific cam:
CCA-20-222-3 COMP Cams Xtreme Energy Camshaft
Hydraulic Flat Tappet, Advertised Duration 262/ 270, Lift .462/ .470
 
That is not a bad grind. I am running the next size up, which is a XE268 with .477/.480 lift. It has a nice sounding chop and still has great low end torque and easily pulls to 5500, even with near stock compression TRW replacement pistons. I am running a Hughes 2500 stall and 3.21 gear, although I was running it with a stock TC. A numerically higher number gear would be better, if available.

I wouldnt go any higher than this in a stock compression 318, otherwise, you may start to give up low end torque. Mine is a street cruiser and hwy flyer and will consistantly run high 14s low 15s with the best being a 14.50 so far.

-Justin
 
RedScampi said:
OK, after reading a bewildering array of input, what are your opinions on this specific cam:
CCA-20-222-3 COMP Cams Xtreme Energy Camshaft
Hydraulic Flat Tappet, Advertised Duration 262/ 270, Lift .462/ .470
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I have this cam for sale in a complete comp cams kit if you are looking for one.

It's a really good cam for a 318, right on the edge of what I would put in one myself.

Look in the parts for sale section.
 
crackedback said:
I have this cam for sale in a complete comp cams kit if you are looking for one.

It's a really good cam for a 318, right on the edge of what I would put in one myself.

Look in the parts for sale section.
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Yeah, I was just gonna recommend that......sounds like a good match.
 
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