Hey guys in kinda torn. Currently have my 383 hsr ready to go. Here's my dilemma. The cam in it (lunati 60121) isn't really what I want lope wise. The cam is already degreed and installed we just haven't dropped it in the car yet.

Just found the ***** thumpr line and it sounds a bit more like what I wanted.

Since the cam is already degreed are these specs close enough to just pop out the lunati and drop in the comp?

Or am I up a creek and should i just keep the lunati?

http://www.lunatipower.com/CamSpecCard.aspx?partNumber=60121

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=217&sb=2

 

Whats your compression ratio?

The Thumper will make quite a bit more power but not a cam for a daily driver or much street traffic at all. U will have to match vlv springs with your Thumper cam also and i doubt springs for the voodo cam will be adequate for the Thumper.

If u really want a narley cam them the Thumper is for u. But u will need new vlv springs and the Thumper can handle/utilize more compression.

But if u gonna drive it every day then stay with the voodo cam. Its your choice man.

BTW what does "hsr" mean?

 

I know you said 383 HSR, and that helps alot. But do you have enough head to use the comp cam? Or will you just end up with a poor performing 383.

The lunati cam you listed will sound pretty tame in the 383. It'll go well, and you'll have a ton of torque. But you are right that it won't sound radical. But you shouldn't choose your cam based on idle sound. You should choose it to match your intended build and parts.

The radical lopey cam may sound cool, but might not perform all that great for what you want.

 

HSR = Holley Stealth Ram. Its basically the old Weiland Stealth Ram for dual carbs with a plenum on top. Great budget intake choice for SBC's intending on spinning higher than 5000.

Big cam's aren't for everyone, I agree. I built my engine with an eye towards high RPM performance. And once tuned it'll scream up there. But while its servicible around town, its not happy under 2000rpm. Parking lots and traffic are a bitch. I have to work the clutch hard when it starts to buck.

It doesn't start to respond till 4000rpm, and isn't really on cam till 5000-5500rpm. But it sings to 7000 quite nice.

 

Wish i could put a Stealth Ram in my 4th gen. I cant even buy a Super Ram anymore - good luck finding even a used one.

 

Hsr=Holley Stealth Ram

Valve Springs are the AFR beehive's I wouldn't want to take it past 6000rpm cause of valve float though the thumper has a slightly higher rpm range flirting with the 6k. Still has the 3.42s in the back and a built 700r4 with a low stall because it'll be a daily. as of now mostly highway. Dougs Long tube headers out to Borla. Compression ratio around 10:1. From what I've read my low end should be similar to what it was when it was a stock 350, and It was fun as heck. I just wanted to pick up the powerband a bit.

 

Why. The Lt1 intake is perfect for even semi wild builds. Many never touch it.

 

The radical lopey cam may sound cool, but might not perform all that great for what you want.[/QUOTE]

 

If you want to have a daily driver with creature comforts and good street manners, then stick with what you have. If you make it more into strip car, then you'll really only enjoy it when racing....how often is that going to happen?

 

Sorry OP, not trying to steal your thread. Just want to answer the question.

Yea the stock LT1 intake is a hemholtz design that has no pulse wave peak - runners are to short. Makes a nice flat torque curve though - with most larger than stock cams. But the super ram and HSR would put the power peak right where i want it for the cam im using now - ram jet #14097395. Shorter duration than stock. The cam quits by 5800rpm and one of those intakes would pick up my power curve there. My dyno sheet looks like a nice smooth down turn there, more of a radius than a slope. I do have fun with that cam though - 18.5" Hg vac at idle but burns rubber like nothing.

 

I am NOT a fan of the thumpr cams. They are made to sound cool but leave a lot of power on the table. IMHO they are best suited for 50-70 year olds with a tri 5 chevy that only drives the car to the local car show/cruise in and ice cream shop on the weekend.

The lunati cam will give you much better usable power/performance, and a slight lope to the idle.

If you build for the cool race car idle sound and try to drive the car a lot you will not be happy with the results you get.

Now being a 383 you may be able to run more cam in the thing but would need your detailed build sheet to tell that, but still the thumper cam would not be the right match.

 

Thanks for the feedback guys I appreciate it. I guess Ill just keep the lunati for now, atleast until I can get another daily. The build isnt too radical but for the amount ive spent I should have just gone LS and been done with it. stock rods, cast iron 383 crank, 4.030 2v relief flat tops, 195 afr's, arp bolts throughout, with the hsr, 36 injectors, 52 mm tb. full msd ignition with box, long tubes out to the borla. kinda want a mix of a show car and a daily. something very clean that If i decide to sell it, ill have no issues doing so. Was also told the headers and the exhaust should help with the sound quite a bit.

 

AFR 195cc heads? Did you upgrade the valve springs on those heads? The stock AFR springs are only good to about 6200rpm I believe. Which a crime considering how well they breathe.

I have the 195cc's on my LT1 with the upgraded springs. Am good to about 7200rpm, the short block is good for a hair more. But the PCM stops at 7000rpm.

So when I chose my cam I went with one that brought max power around 6500-6700rpm.

Lloyd Elliot specc'ed it out for me. 231/239 @ .050" on a 110LSA. .587"/.583" lift. You can tell its cammed. And its okay down low, but not great. But I expected that. Wants to be around 4000rpm before you can start to play, anything below that it lacks any real punch.

https://www.youtube.com/watch?v=6CqOuPfT3aM

 

No I didn't. The cams peak powerband is between like 1800-5800 rpm. didn't think it was necessary to upgrade if I'm not taking it that high. Msd Ignition box should keep me under 5900.

 

I wouldn't upgrade the cam then. With the 383 and that lunati cam this engine is really going to be happy in the 1000-5000rpm range. Around town, or when cruising on the highway its just going to want to GO all the time. A small throttle input is going to make the engine respond with gobs of torque.

It may not have the lope you like, but its going to feel great in all street driving situations.

If you aren't using 1.6 Rockers you'll probably want to to take advantage of the flow of the AFRs. They'll be happier with the 1.6s.

 

I am running 1.6's actually.