Whats the advantage. (Cams)

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straightlinespeed

straightlinespeed

Sometimes I pretend to be normal
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Ok I found a Cam grind sheet in my paper work that says my 318 has a stock 340 cam in it. Please correct me if Im wrong. Here are the specs. I believe I have these listed right.

Lift .429/.444
Duration 286/296

Now compared to the XE262 cam that I keep seeing everyone recommend what are the advantages of switching? I dont understand cams at all!

Lift .462/.470
Duration 262/270
 
The stock 340 cam is .429/.444 228/235° @ .050 268/276° advertised with 44° of overlap.
The XE262 is .462/.470 218/224° @ .050 262/270° advertised with 46° of overlap.
The difference is the rate of lift and the duration the valves are open in relation to the higher lift but I don't feel there's going to be much difference. Not because the Comp is that bad, but because the stock 340 cam is pretty good.
 
lets see if this helps...first 340 cam specs are .430/.444 lift and 268/276 duration. so what you have is not stock the 262/270 cam you are asking about is close to stock but has more lift 462/470 and will produce more power in a close rpm range
 
So they took a stock 340 cam (mine) and ground it to give more performance? There are a bunch of other #'s on the sheet but I have no idea what they mean.
 
straightlinespeed said:
So they took a stock 340 cam (mine) and ground it to give more performance? There are a bunch of other #'s on the sheet but I have no idea what they mean.
Click to expand...
NO. MY guess would be it was a replacement cam what are you going for? those numbers look like a old Chevy grind but that's a guess.
 
straightlinespeed said:
So they took a stock 340 cam (mine) and ground it to give more performance? There are a bunch of other #'s on the sheet but I have no idea what they mean.
Click to expand...

Post up a good picture of the paper and someone can fill you in on what it's telling you.
 
moper said:
The stock 340 cam is .429/.444 228/235° @ .050 268/276° advertised with 44° of overlap.
The XE262 is .462/.470 218/224° @ .050 262/270° advertised with 46° of overlap.
The difference is the rate of lift and the duration the valves are open in relation to the higher lift but I don't feel there's going to be much difference. Not because the Comp is that bad, but because the stock 340 cam is pretty good.
Click to expand...

Are you sure about those at .050 degrees.

Look about 20* long from the ones I've seen and heard about being on a cam doctor.
 
crackedback said:
Are you sure about those at .050 degrees.

Look about 20* long from the ones I've seen and heard about being on a cam doctor.
Click to expand...
x2, ive seen one profiled at schneider racing cams right in front of me.it was like 210/221 @50.it was the stock 340 cam that i ran in a mild 318.i replaced with a short duration narrow lsa isky super cam which ran much better in my combo.the 340 cam had longer legs,but the isky was way more responsive and would rpm a good bit faster.the car was much more fun to drive after the swap.
 
I took it off the Mopar.com website for the stiock 340 replacement cam. I don't run MP because of quality so I'd not be surprised if they had it wrong...lol.
 
The XE262 or even the XE268 will run way better than the old 340 cam. The Mopar cams are 40 year old designs, cam profiles have come a long ways since then. MP cams specs are quite suspect, my 284* .484" purple shaft cam measures nowhere close to the rated MP specs.
 
To try and generally answer your "don't understand cams at all" the old cam designs had more duration increase than lift increase to make more power. Then many years ago the trend was much more lift with smaller increases in duration. Then more and more were dual profile with more lift and duration on the exhaust side.
Today you'll find most cams are dual profile with more exhaust than intake with computer designed ramps that are far superior to anything 30-40 yrs ago.

I would suggest looking around some of the cam manufacturers sites and find their technical section which have wonderful explainations for all of those "bunch of other numbers". I'm sure if you do you'll see all the questions about the car and the useage that need to be answered to make a good choice. Good Luck.
 
I noticed the MP replacement cam is quite a bit different/bigger than the original.
 
Thanks for the responses guys. To answer the question what am I looking for. My engine is tired and needs to be rebuilt and of course I would like more performance out of it. When I saw the grind sheet I was intrigued and wondering the differences and why they did a grind on the cam. Attached is a pic.View attachment grind sheet.jpg
 
Ok, So if Im going to buy a cam what cam should I go with and whats the advantages of each? This is a street car that I may take to the track to race in trophy class.

The XE262 or the XE268.

This is a 318 car, 8.75/727. Already has a Edelbrock performer intake with a Edelbrock 600cfm carb.
 
Look at a common 360 4bbl cam and a not so common 340 auto cam...same..or? Generally the higher the duration number ,the peakier the power band. The crate 380/360 had a cam that had a huge flat powerband, thats nice in a street car with a low numerical rear. 4sp can do a hotter cam as it doesnt have an AT drag at idle. You can read for days on cam theory, best to just call a grinder and let them know what you have and what you want.
 
The (stock 340) cam that's in there now is actually a pretty good choice for a mild 318. The Comp XE268 and VooDoo 60403 are modern versions of the same idea. Are they better? Yes. Are they enough better to justify tearing a running engine apart to install? Maybe.

Honestly if I had $500 burning a hole in my pocket there would be other things I'd do first like a low gear set in your transmission, headers, some 302 heads, rebuilt front suspension, etc... If you are running an otherwise basically stock 318 (that is, stock heads, valve sizes and low compression) you have plenty of cam now, more won't make you faster.

As said before, what about your gearing? Torque converter? Exhaust?
 
im planing on doing a swap this year aswell and im iterested on getting the right cam for my motor aswell i have a 360 in my dart which was built for a ramcharger to go off roading with not sure of the cam size in it but im thinking its a r/v style cam as it sounds really mild. my car is a auto/ 8 3/4 rear with 3:23's headers and a 650cfm thunder series eldebrock carb along with the 318/360 performer intake i also have a single plain M1 intake aswell just send me a pm as i dont want to take over this thread i just figured i'd throw this out here seeing how straightline aready started this thanks
 
moper said:
I took it off the Mopar.com website for the stiock 340 replacement cam. I don't run MP because of quality so I'd not be surprised if they had it wrong...lol.
Click to expand...

The 340 replacement cam is a nice step up over stock. A much
larger cam than stock by a good 10*'s or so.


crackedback said:
I noticed the MP replacement cam is quite a bit different/bigger than the original.
Click to expand...

Yup!

straightlinespeed said:
Ok, So if Im going to buy a cam what cam should I go with and whats the advantages of each? This is a street car that I may take to the track to race in trophy class.

The XE262 or the XE268.

This is a 318 car, 8.75/727. Already has a Edelbrock performer intake with a Edelbrock 600cfm carb.
Click to expand...

Which cam? Answer the question, what gears do you have and what size tires?!?!

If it were myself, and the car has 3.23 gears and a stock diameter tire, I'd go with the 268XE and just increase the tire width. I would not enlarger the tire size much. A 245 width would do fine and fit in the wheel well.
 
I believe right now I have 3.73 gears in the car. I have not had the third member out to verify but doing the turn the tire and count the rotations of the drive shaft I believe that is where I came out at. If anything it may be a 3.55 gear.

I have TTI headers on the car. Tire size is stock. I have stock heads on the car but may change those someday. I have not decided on a torque converter yet, that option is open.

The car was pretty snappy the way it was. Since I have to have the engine rebuilt I figured I would try to get a little more out of it. If you need any more info about the car I will be happy to tell you what I know about it.
 
Well, if you're having the engine rebuilt anyhow...

First off, go looking for some better heads. The late 80's "302" castings are as good as it got for LA 318 heads. Cores are reasonably priced and they cost no more to rebuild than any other factory head. 1.88/1.60 (360) valves are a worthwhile upgrade.

A set of big valve "302" heads, KB167 pistons http://chucker54.stores.yahoo.net/3185ctop6495.html and a more modern 268 degree cam http://chucker54.stores.yahoo.net/vohydcamkitc.html would make a nice running 318 for not a lot of cash.

Add a slightly more aggressive torque converter and go Nova hunting.
 
I like the Cheifs plan.

3.73 gears would be very odd to have for a MoPar.
 
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