The always elusive CAM question..

[POPS6T6]

Another item that I have found to have been discussed in great detail and so much information out there that it actually leaves me shaking my head wondering what I just read. Obviously I am more of a fabricator body guy than an engine guy. You want a bike built? I'm your guy, you want engine advice, don't ask.. Just not something I have ever been able to grasp.. Now with my honesty being put out there I am hoping for some advice here and also know, I don't know everything, but hoping to give as much possible information that I do know to get the best possible answer..

With that all being said and out of the way.. I am currently having my engine machined for my 1966 Barracuda which has disc brakes, 8 3/4 rear end suregrip and 727 automatic transmission. It is a 360, bored 30 over, Keith Black racing pistons, roller rockers, air gap intake and J heads (have not been milled to match yet and if the advice includes what to do with those, even better). The guy working on it is a friend and dirt track racer, so he is good with the machining part, just not with the specs part if that makes sense. I had built a 318 that was bored 60 over and had the Crane Cam: Hydraulic Flat Tappet, Advertised Duration 278/290, Lift .467/.494, installed, and I really liked the sound and it ran quite well with a 2000 stall on it. For this motor, being a 360 and needing lifters and springs and timing I was hoping to buy a "kit" that includes it all. This car will not be on the strip, primarily on the strip, but I do want it to sound and run good. Emphasis on running good more than sounding good. Here are the cams I am stuck on and also know I have no idea what the #'s mean on these as well!

http://www.summitracing.com/parts/cca-k20-224-4
Cam/Lifters/Valvetrain, Hydraulic Flat Tappet, Adv. Duration 274/286, Lift .488/.491, Mopar, 273-360, Kit

http://www.summitracing.com/parts/cca-k20-223-3
Cam/Lifters/Valvetrain, Hydraulic Flat Tappet, Adv. Duration 268/280, Lift .477/.480, Mopar, 273-360, Kit

http://www.summitracing.com/parts/cca-k20-418-3
Cam/Lifters/Valvetrain, Hydraulic Flat Tappet, Adv. Duration 275/284, Lift .462/.482, Mopar, 273-360, Kit

With a 2-3000 stall convertor, I am leaning more towards the first Cam (274/286, Lift .488/.491,), but is that to big? Will there be vacum issues (something I just learned about reading today) Or will that cam give me the low end hp and yet still be street reliable/driveable?

Sorry for beating a dead horse, I have tried and spend the last 3 days reading and re-reading and seems I am only getting further lost.

Thanks in advance!
J

 

[cudavert]

......and had the Crane Cam: Hydraulic Flat Tappet, Advertised Duration 278/290, Lift .467/.494, installed, and I really liked the sound and it ran quite well with a 2000 stall on it.

http://www.summitracing.com/parts/cca-k20-224-4
Cam/Lifters/Valvetrain, Hydraulic Flat Tappet, Adv. Duration 274/286, Lift .488/.491, Mopar, 273-360, Kit

http://www.summitracing.com/parts/cca-k20-223-3
Cam/Lifters/Valvetrain, Hydraulic Flat Tappet, Adv. Duration 268/280, Lift .477/.480, Mopar, 273-360, Kit

http://www.summitracing.com/parts/cca-k20-418-3
Cam/Lifters/Valvetrain, Hydraulic Flat Tappet, Adv. Duration 275/284, Lift .462/.482, Mopar, 273-360, Kit

With a 2-3000 stall convertor, I am leaning more towards the first Cam (274/286, Lift .488/.491,), but is that to big? Will there be vacum issues (something I just learned about reading today) Or will that cam give me the low end hp and yet still be street reliable/driveable?

I'm running the cam (in bold print) in an old 70's Z28 350 I own. I like it. It's not too crazy and I'd think it would be compatible with a fairly decent build as you're describing, and it does have a noticeable lope, but not a vacuum-killing lope. That cam in the bottom link just sounds odd to me! 219/235@ .050?! And the cam in that 1st link may be a bit too hot, IMO......just my .02.

 

[RustyRatRod]

Trust me when I say cam questions are not elusive around here at all.

 

[POPS6T6]

Trust me when I say cam questions are not elusive around here at all.

Guess I should have said "The elusive CAM answer"....

 

[POPS6T6]

I'm running the cam (in bold print) in an old 70's Z28 350 I own. I like it. It's not too crazy and I'd think it would be compatible with a fairly decent build as you're describing, and it does have a noticeable lope, but not a vacuum-killing lope. That cam in the bottom link just sounds odd to me! 219/235@ .050?! And the cam in that 1st link may be a bit too hot, IMO......just my .02.

I am not familiar with all the #'s. I was hoping to get as close to my old cam as I really liked that one, but I also don't want the vacumn issues. Thanks for the input!

 

[RustyRatRod]

Guess I should have said "The elusive CAM answer"....

No, you had it right. YOUR question was extremely elusive. Your long winded question left out all of the pertinent information. What's the blueprinted compression going to be? What converter? I saw 2000 stall, is that what you're going back with? What gear? Are the heads going to be ported? Valve sizes? What intake manifold? Headers or manifolds? That particular Crane cam is a GREAT one for very mild builds. It is one of my favorites. If you can give more information, we can get you closer.

 

[dano]

Have you considered one of the Lunati VooDoo cams since you plan on changing the springs?

 

[tubtar]

Call a cam grinder that knows MoPars ( probably not Comp ) and let them help you pick a grind.
Hughes and Bullet are two nice choices....I use Bullet myself.
be honest about what you want and what you have and they will hook you up.
I am not saying Comp makes bad products , but their lobe selection is Chevy centric and so is their tech line.
Their cams will work , but matching the intake and exhaust lobes with what your end use is gonna be will get you closer to perfect than one of their shelf cams I bet.

 

[POPS6T6]

No, you had it right. YOUR question was extremely elusive. Your long winded question left out all of the pertinent information. What's the blueprinted compression going to be? What converter? I saw 2000 stall, is that what you're going back with? What gear? Are the heads going to be ported? Valve sizes? What intake manifold? Headers or manifolds? That particular Crane cam is a GREAT one for very mild builds. It is one of my favorites. If you can give more information, we can get you closer.

And that is exactly what I was getting at. No knowledge of engines.. Thanks for re-pointing out the obvious. (Making fun of myself there)

I am basically building the motor with stock J heads, no porting and stock valves and no machining as of yet (if needed I can and will get them milled or whatever). I will be using headers (not determined yet, firewall headers) the rearend is 8 3/4 with what I believe is 4/10 gears and if necessary to run a bigger cam I would go with whatever stall converter was needed. The intake is a Pro Products Crosswind (for now, hoping to upgrade to the edlebrock air gap, but the crosswind was free and going to try to give it a run)

 

[airwoofer]

I liked the Comp PP508 cam I have in the 340 and had in the 416.

 

[cudavert]

.....n/m........

 

[RustyRatRod]

Well, unless you know about what compression you will end up with, you can take every single one of these cam recommendations and throw them in the garbage. What I would advise you to do would be to wait until you get stuff in the machine shop. Let them CC your heads. Find out what pistons you have. I would GUESS the KB107 flat top with 2 valve reliefs....but you need to be sure. Once you have all of that info, then we can help with a cam. IMO, people should not throw out a recommendation without know all of the parameters, because it might not be a good one. That's why I ask, ask, ask. Because I don't want someone choosing one of my recommendations and ending up unhappy.

 

[cudavert]

Well, unless you know about what compression you will end up with, you can take every single one of these cam recommendations and throw them in the garbage.......IMO, people should not throw out a recommendation without know all of the parameters, because it might not be a good one. That's why I ask, ask, ask. Because I don't want someone choosing one of my recommendations and ending up unhappy.

Whatever.......I was basing off running between 9.5 and 10 to 1, maybe I was wrong for assuming. Much less than that, and his whole performance package would be ridiculous. This ain't brain surgery.

 

[RustyRatRod]

I agree. I wasn't bashing anybody's suggestions. Simply saying we need as much info as possible. KB makes a wide variety of pistons. We can assume what he has, but we don't know.

 

[273]

Cam should be one of the first thing you should dicide on not the last and picking cam on sound isn't the best idea either. An engine, drive train, cars weight and purpose has to work together as a complete package.

 

[RustyRatRod]

The cam first? How do you know what cam without knowing compression, head flow, intake, exhaust, converter, gear and on and on? I've chosen cams first in the past and they always get changed depending on the outcome of other parameters.

 

[POPS6T6]

And this is why I am here.. I am trying to get the information you asked about, to be honest I didn't have a clue where to start and I realize this is annoyance to some of the more seasoned engine veterans out there, but at the same time, there are plenty of people out there wondering the same thing but just to scared to ask. So I ask questions and based on the responses however demeaning or critical they are, I still respond and try to get the information correct in order to find the correct set up. The pistons are the KB107s, the intake is the pro products crosswind, headers have not been chosen yet, right now the convertor is stock, but I can easily change that out to 2 or 3k or whatever works for the cam chosen. Currently the heads have not been zero decked, but if that is the suggestion, then they will be. I never understood engine setups, this is all foreign and out of my league, that's why I am here.

 

[RustyRatRod]

The block is what you zero deck height. In other words, that means you mill the block until the deck surface is flush with the piston at TDC (top dead center). No annoyance at all. I simply want to make damn SURE of what you have before giving you any advice. You don't HAVE to zero deck the block. However, Chrysler blocks are known for their deck surfaces being uneven, so it's a good idea to square them up. Since the cost is the same, zero decking is a good idea. If you have the KB107s, then to zero deck height the block, you need to mill .012 under the 9.6" deck height. That means your deck height should be 9.588", BUT, you might end up milling .050" to get there, because the decks are generally high. But 9.588" is the number you need for zero deck height. You'll end up with probably 10:1 or a tad more, so you'll need a healthy camshaft in order to run on pump gas. I would say something in the 240-250* duration @ .050 area. Probably closer to 250. All of this of course is just my opinion. I am sure there'll be others.

 

[273]

I should of said early in the design process, first is purpose then to power to weigh ratio then powerband then engine size then cam and head combo then match gearing, intake,carb, compression etc... You should know your cam before machine works begun.

I just see lots on here saying something like I got a 3800lb car with 8.5:1cr, 2:73gear, stock stall, single plane, ported J heads, daily driver and want to sound like a race car which cam?

 

[POPS6T6]

That actually made sense! I think I need to make sure he has the block done correctly and sounds like zero decking is the first step. I guess this is just a follow up question, what if I don't zero deck? Is that something that is required? How would that affect compression which in turn how would that affect the cam choice?

 

[RustyRatRod]

If that made sense, then I am out. How you can pick a cam BEFORE final machining is beyond me. That means to pick a cam BEFORE you know your final compression ratio. Makes no sense. Good luck sir.

 

[273]

I agree with ya we need to know the exact CR before you can decide on cam that's the situation we have but I would like to know ruffly the cam spec first and let that determine my CR, stall and final gear ratio than the other way around. And yes I think you should know what cam your gonna run before machine especially on more radical ones, piston to valve clearance, CR and valve spring heights etc... Are gonna be effected by cam choice.

 

[POPS6T6]

If that made sense, then I am out. How you can pick a cam BEFORE final machining is beyond me. That means to pick a cam BEFORE you know your final compression ratio. Makes no sense. Good luck sir.

I haven't picked a cam and that was the point to this entire question. The guy who is prepping the block wasn't going to zero deck it. He was going to bore and home it to straighten it up. But the more I read the more it seems to get the more bang for your buck you should perhaps zero deck the block.

But thanks for the good luck wishes.. After all this, maybe having a little luck isn't such a bad thing..

 

[POPS6T6]

I agree with ya we need to know the exact CR before you can decide on cam that's the situation we have but I would like to know ruffly the cam spec first and let that determine my CR, stall and final gear ratio than the other way around. And yes I think you should know what cam your gonna run before machine especially on more radical ones, piston to valve clearance, CR and valve spring heights etc... Are gonna be effected by cam choice.

Thank you.. That's about how I was going about it.. Everyone approaches problems differently..

 

[moper]

This is a little more rough than it needs to be. If you're running KB107s, and you're running factory heads of some sort, you will generally end up with a static comptression between 9 and 9.8:1. Unless you blueprint the block and heads and are careful about head gasket choice you won't reach 10:1. "Blueprinting" means taking care to machine the parts down to what the factory said they were supposed to be. Normally the block surfaces are "tall", and the head chambers are "large" compared to what published specs. If you have a valve job done and keep the valves, the chambers get even bigger. So - really it's not a big deal. The only question is do you need vacuum for power assist brakes? If you have power brakes, look at a cam around 225-230° @ .050. So of the three you posted - #1 (XE274H) is too large for power brakes but a decent 360 cam if you don't need vacuum for brakes. #2 (XE268H) is the largest one I'd use and the best "all around". I've used many of them and they run great. #3 will work but IMO you're leaving a little on the table in terms of performance.
With what you should end up with for static non of these cams should have too much cylinder pressure so they are all pump gas, which octane will depend on your tuning and the fuel you can buy locally.