Which of these two cams?

[MOPARJ]

I am looking to give my Darts 318 a little more low end torque and a little more high rpm energy, as it is pretty soft above 4,500 rpm (imagine that with the stock cam with its paltry .390 or so lift.

I have a Comp 260H cam that is in a storage box that I have had on the shelf for about 6 months. This cam served about 3,000 miles of duty in the 318 in my duster before the motor was rebuilt and a XE268 replaced it. The 260H has .440/.440 lift and a 110 LSA. I am thinking about reusing this cam, as I had no issues mechanically with it.

I was also thinking about stepping up to either a XE256 or XE262. Would either of these perform better and be worth spending the extra money on, or should I just save my money and use the used 260H and will it give me substantial gains over stock? I currently run dual flowmaster exhaust, 2 1/4 piping, and a Holley 600 cfm carb perched on a Edelbrock manifold.

My goal is for an even peppier motor over what I have now, for little dough. I want to replace the timing setup with a roller unit and steel gears, so why not kill two birds at one time.

 

[AdamR]

If you have the 260H that would be my first choice just because you all ready own it. Next would be the XE256

 

[fishy68]

Use what you got. The 260H will probably have better low end torque and peak about 4500 but still pull to 5000. The Xe series will probably give a little more top end power but not much difference in bottom end torque. Maybe even less low end torque. You should gain a little low end torque boost and maybe as much as 40 hp on the top end. Make sure you get a true roller timing set also. Allot of sets out there are just double roller chains that aren't true roller designs. A standard double roller isn't much better than a stock silent chain. A true roller rotates with a little less friction and lasts much longer and they don't usually cost much more.

 

[MOPARJ]

Use what you got. The 260H will probably have better low end torque and peak about 4500 but still pull to 5000. The Xe series will probably give a little more top end power but not much difference in bottom end torque. Maybe even less low end torque. You should gain a little low end torque boost and maybe as much as 40 hp on the top end. Make sure you get a true roller timing set also. Allot of sets out there are just double roller chains that aren't true roller designs. A standard double roller isn't much better than a stock silent chain. A true roller rotates with a little less friction and lasts much longer and they don't usually cost much more.

Agreed. Even a little more top end would be nice, which the 260H would probably do. Right now, the stock cam has decent low end, but is just out of breath by 4,400 rpm and I dont rev it higher than 5,000 when I am on it hard, as it just doesnt make power there anyways.

 

[rumblefish360]

Headers or exhaust manifolds?

 

[MOPARJ]

Headers or exhaust manifolds?

Manifolds currently...maybe headers later on.......maybe, since this is just a cruiser.

May do it anyways to try to eek a little better effiency out of the motor, as it seems to be only averaging 11-12 mpg total with mixed driving per tank when I do the math. It should do a little better than that with the stock cam.

 

[ramcharger]

I'd drop in the 260H cam, replace the head gaskets with the MP .020 thick gaskets to boost your compression a bit set your timing to 10 BTDC and tune from there.

Any bigger cam than that and you won't be happy with the loss of low end torque due to the low stock compression ratio.

Is the Holley a vacuum secondary model?

Also, what rear gear are you running?

 

[needsaresto]

I was thinking of this one for myself.

http://www.fastengineparts.com/products_view.php?id=1528

It's an older clevite grind. I ran it on D.D and my combo really likes it! Not quite as much tq as a comp cam but it is 1/2 the price.

 

[needsaresto]

Just downloaded camquest. My magnum la 318 is predicted to make almost 400 h.p and 400 ft/lb of torque with the 262xe.

Call me cynical,but I kinda doubt that. Seems like I'd need a bigger cam for #'s that high.

That program seems to only allow for comp cams? Am I missing something?

How about this cam for torque?

http://store.summitracing.com/partdetail.asp?part=CCA-20-221-3&autoview=sku

Says you cannot use stock springs?

I say hogwash.

 

[rumblefish360]

Stop penny piching and get the springs. Do the right thing.

I'm running a comparable Crane. Very good and mello idle. Almost feels/sounds stock. It's on a 112 C-line. http://cranecams.com/?show=browsePa...=318 C.I.&partNumber=693941&partType=camshaft

 

[ramcharger]

I'm running that same cam in my Ramcharger's 360 but I'm running a 10.2:1 compression ratio and 1.6 ratio rockers. Very stock type idle.

 

[dodge freak]

The high the compression, the better the idle and vacuum.

 

[AdamR]

Just downloaded camquest. My magnum la 318

I have cam quest also. Its very generous with its hp ratings.

 

[fishy68]

I have cam quest also. Its very generous with its hp ratings.

Noticed the same here. I also noticed allot depends on which intake type you select. Go with a standard dual plane intake and it comes close to what desktop dyno says with all the other inputs being the same. Switch it to a high flow dual plane and it gains about 75 hp. I have a real hard time believing that.

 

[fishy68]

Just downloaded camquest. My magnum la 318 is predicted to make almost 400 h.p and 400 ft/lb of torque with the 262xe.

Call me cynical,but I kinda doubt that. Seems like I'd need a bigger cam for #'s that high.

That program seems to only allow for comp cams? Am I missing something?

How about this cam for torque?

http://store.summitracing.com/partdetail.asp?part=CCA-20-221-3&autoview=sku

Says you cannot use stock springs?

I say hogwash.

Did you put in actual head flow numbers from a stock magnum head or did you select one of the generic heads they have listed? I also highly doubt a 318 with that little cam will make 400 hp.

Your right you can't change the cams to any others. Won't let you change the parameters like desktop dyno.

 

[mullinax95]

With the information you gave above your motor with each cam:

260H
HP 227@4500
TQ 318@3500

XE256
HP 235@4500
TQ 321@3500

XE268
HP 240@5000
TQ 311@3500

 

[MOPARJ]

With the information you gave above your motor with each cam:

260H
HP 227@4500
TQ 318@3500

XE256
HP 235@4500
TQ 321@3500

XE268
HP 240@5000
TQ 311@3500

The numbers seem right for the XE268. That is what the motor in my duster has. 8:5:1 compression, same manifold, except a quicker advance curve, Holley 650 vacuum secondary, and hooker headers. I would think with the carb and headers I would be pushing 260-275 in horsepower and probably 330-340 of torque. It feels almost as quick as a stock 340 right now, so maybe.

What does the program say for that combo?

 

[needsaresto]

Did you put in actual head flow numbers from a stock magnum head or did you select one of the generic heads they have listed? I also highly doubt a 318 with that little cam will make 400 hp.

Your right you can't change the cams to any others. Won't let you change the parameters like desktop dyno.

I used some custom head flow #'s from my ported magnums.

But I still doubt 400 h.p!