360 cam choice

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trbodrt

trbodrt

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building a street 360, would like to get what performance i can out of it, I understand rpm range and intended use play a part in cam choice, but what factors go into choosing a cam. Deciding between hydraulic or mechanical, duration and lift. I don't want to just stab a random cam in it and go, i would really like to understand how to make the right choice. Here are the car specs, stock 360 block externally balanced, 10 to 1, kb 107's zero decked, stock crank polished, scat i beams, stock heads w/ 2.02s, 3 angle valve job
(would like to step it up later), 1.5 roller rockers. rpm air gap intake, 750 demon. will be running a 904 and and an 8 3/4 with 3.73's. wont know converter untill cam is choosen. Any advice and knowledge you guys can bestow upon me would be appreciated
 
This is a great question and should be a danm sticky since it is a frequent question.

The way I look/think/choose a cam is dependent alot of what exactly I'm doing with the car, it's intended purpose. We all know (Or should remember) the 3 keys to a decently performing engine. The 3 C's. Cam, Compresion, carb size. (The 4th "C" is converter) and they have to work with the cars (Converter) weight, gear ratio and performance arena.

To much or not enuff of one of the C's will lead to a less than stella performer.

I have run a zero deck 360 a few times before. I like this set up alot for a street, street/strip performer alot.

What I do is start with the intended performance. In this case, it seems your looking for a really nice street light warrior. Being limited by the heads and it's ratio of 10-1. (Ruffly, close enuff for this dicussion, rounding it off is acceptable)

Next, look at the cams duration. The duration will dictate the RPM range of it's operation.
Then lift. For a general rule, for the street, not track, I run as much lift as the head can handle. In otherwords, if the heads ports flow well up to .500 lift, I keep lift right at about .500 and not much more. The head flow stalls after that point, theres little reason to continue lifting the valve passed this point.
While some will argue, remember gang, this is only a street engine and going balls out max is not required or needed.

Then the cams centerline. 110 is the most common centerline and works well, though a hot 360 can go to 108 for the street.
 
Okay so duration=rpm range, and stay around lift of what head can flow max, then what decides hydraulic or mechanical and what would work better with this combo. Also what cam and converter would you recommend with this combo.
 
There's a ton of stuff that can go into the cam choice. Real mechanical items like static and dynamic compression ratios, intake tract, exhaust system design, convertor, rear gearing, vehicle weight, fuel type, chamber design, piston design, and technical class restrictions. Then there's the less tangible things like intended use, expected rpm ranges, ease of setup, possible maintenance reruirements, possible break in issues, builder comfort level, and cost. The fact is it's a critical part, but as many of the issues that go into choosing the right one become less important than others as the intended use gets more broad, the milder the package, the less critical things become. With no class restrictions, a broad rpm range, and multiple usage expected, your cam choice isnt really that difficult. Something simple to install, that will be easy to break in, won't cost a fortune, and provide good throttle reponse and a broad torque curve is what you need. This is where it takes a subjective turn. Some like MP, some like certain other name brands. Some will argue what they have is best but might not actually have the experience to say if anything else might be better. Some have had bad experiences and their choices will be different. I use a lot of Comp Cams stuff. I've never had a bad experience with any of the brands I've used. These include Crane, Engle, Lunati, Summit brand, Bullet, Ultradyne (before Bullet), Wolverine, MP, and Sealed Power over the years. For a while I was finding clearance Crane stuff fairly cheap and new in the box. Crane IMO is one of the best street cam makers out there in terms of quality and design. My "first choice" would be the 693903: 260/272, Lift .427/.454. A cheaper second choice would be the Summit K-6900 cam which is I think about 50% cheaper. Another good one would be the XE268 Comp. I actually have the XE262 in my truck and I love it.
 
You decide of which will be used mech. or Hyd. cam.

I can generalize a converter, but IMO, I would seek a pro's advice in the arena you want to perform in. Like Dynamic converters for example of one amoung a few good spots.

And as far as cam goes, you choose one. Theres not exactly a right or wrong or what not. Just enjoy this as an exercise. You list below 3 cams.

(Since Moper responded while I was writing this, excellent answer Moper.)

Now in addition to Mopers answer, I believe you are armed to make a choice without being far off base in any direction. I love that Moper said "Subjective" in his reply. Truly, that is the case in cam choice. Even if you had a dyno at your side and free run time for a month, the coice in the final cam you make is a combonation of things.

I know you and others here have noticed that when the topic of cams show up, the opinions come pooring in like made and the personal picks and picks based on theroy off what will work best vary wide and sometimes greatly.

IMO, being armed with these 2 posts, I beileve the cam choice you make will be good. But allways subject to someones opinion on what could be better, what you should have choosen and even a comment of "What are you nutz?!?!" will appear here and in person.
 
In the past, I have run with my Edelbrock heads on a zero deck 360 combo are ;

Purple 292/.509/110 Hyd
Comp 296/.525/110 Mech
A Crane 288 and a.5+ lift. Hyd. split (I forget the exact specs, it's beena long time)

I want to try a Comp solid roller and a Lunati solid roller that both have about that max lift as listed, AKA W/therorectical lift of what the head can take at max. lift. Though theres probably little difference between the cams when the butt dyno is done.
 
This is the cam i have been looking at, it's a lunati cam and lifter kit, I do plan on possibly porting my heads or stepping up to some rhs or edelbrock heads in the future. Let me know if this will work out with what i have right now.

  • Advertised Duration (Int/Exh): 268/276
  • Duration @ .050 (Int/Exh): 226/234
  • Gross Valve Lift (Int/Exh): .494/.513
  • LSA/ICL: 110/106
  • Valve Lash (Int/Exh): Hyd/Hyd
  • RPM Range: 1800-6200
 
I think it's a little big, but it will work with what you have. I don't think it will run power brakes in case you have them. Also, you need to run the dual springs Lunati recommends, and you need to break in the cam without the inner springs in place.
 
That Voodoo cam will work real good in your 360. And it will love a head swap if you ever do that. For a 10 to 1 360, this cam is not to big. Plus I see no reason why you could not run power breaks. It has only 52* overlap, and I'll bet you pull 13-15inches of vacuum at idle.

I have built a few 318's with this cam, and I tell ya, they run strong. And in a 360, they make a ton of torque, which is great for a street engine.
 
I agree with MRL, defenitly not to big. I see no issue with running that cam. In the future, be it RHS or Edelbrock heads or simply porting what you have, the improved cylinder head flow will add a nice and noticeable power increase.

With your current stock heads, check the clearances with the retainer to valve seal and make sure the head has room to run that amount of lift. There should be no issue with clearance, but just check anyway.

There should be enuff vacuum to run power brakes without concern.
 
thanks for the advice guys, I think i will go with that lunati cam, it's what i've been leaning towards. It's all about trial and error.
 
The only issue that makes me say there might be other choices is the stated compression ratio.
For two reasons:
1. Typically, KB107s are not zero deck unless the block is square decked to 9. make them so. Just a deck clean up leaves thme down in the hole anywhere from .020-.005 depending on how tall the factory left it.
2. Open chamber mopar heads are always much larger than the factory spec, and valve jobs without seats or valves tend to keep that large even with the deck surface cleanup cut. So the reality of it is using the MP thin gasket, you're still closer to 9.5:1 than 10, and that might bring down the idle vacuum.

However, I agreee with a decent head over it, and a little more static compression, it will be a perfect match.
 
I had the machine shop square the deck up with the mains after the previous owner had the block decked before his rebuild, got totally lucky and the piston ended up sitting in the hole about 1 thousandths down if that.
 
Cool. The difference between "putting together" and "building" are the extra checks to make sure everything is what it needs to be.
 
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