SBC Camshafts - Suggestion

In my current project; I am running a built SBC motor (Flattop Pistons (higher than stock compression), Camel Hump Heads, STock rockers (or can change that upon recommendation) Dual spring valve springs, Triple deuce intake and want to run the most radical sounding cam that I can find. Car will be running an early Corvette 4-speed transmission.

The car will be mostly on the street, maybe to the strip from time to time. The car is going to be a straight axle g***er.

I really want something that will work well and sound healthy.

Im not very knowledgeable on them and really dont know where to start.

A good friend suggested a Duntov 57 cam grind, but I think that one is pretty mild.

Any suggestions, education and/or sound clips that they can share?

Thanks.

 

Comp Cams Thumpr series. I have no actual experience with this camk, but sounds like it would fill the bill.

 

Whatever you pick, don't be afraid to advance the cam plenty.

Picks up torque and driveability so you can enjoy the sound and still pull away from a stop sign or outrun your pals!! K

 

Devin is in track with his idea. You will have to change rockers because the stock Chevy rockers can only handle up to .480 lift. I'll suggest some kind of roller rocker. Comp's Thumpr cams can be bought as flat tappet or hydraulic roller retrofit kits.
They get their sound from the lobe seperation angle being 107 degrees as opposed to vacuum making smooth stockers having 112 to 114 LSA.

 

Be very careful on lift unless you plan to tear the engine back down to the shortblock so you can check valve to piston clearance. Plus unless you know EXACTLY what your valve springs are you could get into coil bind. Also if you want the proper "sound" then solid lifters are a MUST. Gotta have that sewing machine "whir", no self respecting gearhead in the g***er days ran hydraulics.

The Isky Z-30 Solid Lifter cam looks like a good choice. With only .480" lift it should keep you safe on valve clearance and coil bind on the springs but lots of duration and 108* LSA should give it a real lopey idle. Besides what's more traditional than runnin' an ISKY?

 

Comp Cams Extreme-Energy series is what we use the most of. Cam # 12-250-3 is what I would recomend for the result your asking for. 507-510 lift 284-296 duration. Good bark and good bite for the money. My experience with these are that they idle fairly aggressive and as soon as you pop the throttle they smooth out and haul serious ***. The best of both worlds >>>>.

 

I would go with a custom grind if there is not an off the shelf grind that does what you want. I would need to know a lot more about your motor - like true compression ratio, what lift can the springs take, how many cubic inches, how well do the heads flow, do you want solid, or hydralic lifters?

For example:

I am building a 10.2:1 406 sbc with good flowing Iron Eagle 215cc heads. The heads are untouched with 2.05 intake valves, valve springs good to .600 lift, a 64cc chamber, and the engine will be equipped with a good flowing intake (Victor Jr) and headers with a full good flowing exhaust.

Flow looks like this @ 28".

Lift / intake / exhaust
<TABLE><TBODY><TR><TD>0.100</TD><TD>65</TD><TD></TD><TD>59</TD><TD></TD></TR><TR><TD>0.200</TD><TD>129</TD><TD></TD><TD>112</TD><TD></TD></TR><TR><TD>0.300</TD><TD>182</TD><TD></TD><TD>139</TD><TD></TD></TR><TR><TD>0.400</TD><TD>226</TD><TD></TD><TD>166</TD><TD></TD></TR><TR><TD>0.500</TD><TD>258</TD><TD></TD><TD>178</TD><TD></TD></TR><TR><TD>0.600</TD><TD>255</TD><TD></TD><TD>186</TD><TD></TD></TR></TBODY></TABLE>

You may notice that the I/E flow ratio averages out to around 75% on these heads, which means that they respond to a dual pattern camshaft with more exhaust duration.

I want low maintainace and don't need more that 6000-6500rpm which means a hydralic camshaft of some type will work well. I don't feel like spending the extra $1000 for a hydralic roller camshaft either, so it looks like a hydralic flat tappet will fit the bill nicely. Since this is a street car, I don't want drag racing lobes - something a little gentler is neede to survive.

I have big cubes and will be running a four speed which means I can run a hotter cam since both tend to tame camshafts. I want the car to have decent street manners, so I will probably be looking at a camshaft with a duration on the intake of under 250 @ 50. I want it to be able to pull well up to 6500rpm, so I am going to need a bunch of duration - at least 240 @ 50.

I like a snotty idle, and all undervalved engines like the 400sbc tend to make more power with a tighter lobe seperation, so I will go with a tighter lobe sep. 110-112 degrees is about average on performance cams, and the factories usually run 115-119 degrees on their cams for emissions reasons. I am going to go with something about 106 degrees

So now, I am looking for a dual pattern hydralic flat tappet camshaft with under .600 lift, between 240 and 250 degrees duration on the intake, and a tight lobe seperation angle. Going to my Comp cams Catalogue and looking through it gives me grind 295TH7, part number 12-602-4, which is from the Mutha Thumper series. Its packing some serious duration - 295/313 advertised, 243/257 @ 50 on a tight 107 lobe seperation angle.

It also has some decent lift with 1.5" rockers - .501 on the intake and .486 on the exhaust. I personally like big soft lobes on the street, and that exhaust lobe is definately that! It might respond well to more lift also, like using a 1.6 or 1.65 ratio rocker.

The only thing I don't like about that cam is the 5 degrees of advance ground into it, but an offset bushing in the timing chain will fix that.

You should go through a similar process in picking a cam for your car.

 

I used an Isky 280 Hydraulic in a 327 I built years ago (w/fuelie heads). It would rev but still built excellent mid-range power.

-Lee
Atomic Radio
www.atomicpinup.com

 

just remember you'll need some vacuum to **** the gas through that 3 - 2 set up so it will idle. I had a 292H in my 383 and had to change to a 268XE to get vacuum to idle it.

 

sounds like what im looking for. Solid lifters and lopey idle. Thanks

 

You do realize you will be adjusting those solid lifters fairly frequently I ***ume. Like every other oil change maybe.

 

I've sworn off belly****on engines, but somehow I couldn't give up my (still in the factory tube) 140 service mechanical cam. Of course it would take short stroke short block with GOOD flowing heads, a light car, and stiff gears to make it work, but what music!

 

Call Comp Cams ask for Chris Pagent tell him what you have in the engine and what you want.He knows his **** and will get you what you need.

 

Ive had just about every cam manufacturer in my small block and big chevys and lunati has since been my favorite. I just put a small VooDoo cam in last season for a street/strip camaro and i love it. lopey idle with out having to put screw in studs or anything like that, just a quick swap. Though if i had a thicker wallet i would put a Thumper cam in i just cant afford the rockers to retrofit the damn thing. Lunati also has great customer service dudes. I called them to rave about the cam and they shipped me a free 10' poster. ........ lol. Just my 2 cents.

 

Crower ground a hydraulic version of the old LT-1 cam for me...

242/254 @ .050
.459/.485 lift
116 LSA

I wanted the wide LSA to facilitate building vacuum for my tri-power induction.

 

This is so sad.
Every single "request for cam advice" begins with "how does it sound".
The rilly kewlll sound is not healthy power.
It's the sound your dog makes choking on a chicken bone.

 

If you've got it torn apart screw in studs and guide plates will keep everything where it's supposed to be.

 

so were not out of context of the initial request; I asked first on performance then sound:

"I really want something that will work well and sound healthy."

To most 'outsiders', isnt the sound that gets people excited first?

 

Email Comp Cams ands they can reccomend the cam that will work best.

 

I built a very similar 406 a few years ago. I got a killer deal on a new Crane "saturday night special" stock car grind. It sounded like a big block and ran to 6000rpm at least 2000 times and still runs down the highway all day long. My '57 Ford went 13.0 @ 101. at Da'Grove and got 16mpg with a 700R4 and 3.70 gears. I used stock-type long slot rockers.

As for the original question; solid axle? 4spd? gotta have a solid!!!!!!!! screw in studs, long slot rockers, and CORRECT valve springs are a must.

 

I've got a Hot 283 with 3 deuces. Running a comp cams 270. Sounds great and has good balance of mileage and power. With the motor you are describing, if you go much bigger without more mods to the motor, you will start losing performance.
If sound through a parking lot is most important then go with a 30-30 Duntov.

 

How bout this one? Lunati BareBones cam and lifter kit. Dur.290/300, Dur.@.50 224/234, Gross lift 465/488, Lobe sep.112 and rpm range of 2-6k. $125.99

 

Look at Elgin or Speed pro perfomance cams . Go to this Website www.compe***ionproducts.com . Kits for $140.00 with cam springs and lifters .

 

I myself love solid cams and have solid rollers in 3 of my cars...however...I recently used a hydraulic roller "thumper" from comp in my gals '57. It was the smallest of the series, and put its in a 10:1 383. I highly recommend it...sounds great (like a lot bigger cam) and always turns heads, maintenance free, and has plenty of beans. Like someone else posted, the 107 lobe seperation is the key...plenty of torque and seat of the pants feel. By the way, Comp has sound clips on their website...
sam

 

I used to run one of these cams in a 355 I had in an old Vette. Excellent cam & killer idle.

 

had a 280 magnum in a 355....ran good , sounded good. had pretty much the same motor you discribed other than roller tips ... that was more than a decade ago , but it got the job done... if you have the clearance , and gearing...cranes 518/536 /282(ish)288 solid makes good noise and awesome power from 3400 to 6800... ran one in a flat top 406...got one going in a flattop 383 vortec motor.... brandon

 

i've had good luck with comp magnum 292 in 355 chebby on the street (sound and performace), would be willing to use it again....

 

I have a 350 sbc with a wolverine cam (not sure on the size) but sure makes a differnce. nice throaty sound, power and I didn't loose any vac***e. A buddy of mine put the same one in a 305, and had vac***e issues. I saw on the speed chanel where the used a 4/7 switch and got great results with it.

 

Very good advice. They are reliable and cheap. They have a great selection too.

 

Also, if you're wanting to play with rocker ratios, you've got to slot the push-rod guide holes in the stock sbc heads with a "Louis" tool to run the 1.6 ratio.

If you want to run guide plates with screw-in studs, the slotted push-rod guide holes must be drilled out to prevent push-rod binding. The push-rod needs only ONE alignment device, not two.