StealthFormula

iTrader: (35)

*Stock Head Cam/Cam Swap Guide*

Intro:


It seems like several people every week want to know what cam is best for their stock headed setup or what components they need for a cam swap; so this is a guide to steer all of you in the right direction and hopefully allow you to make the optimal choices for your setup.


Part 1: Choosing A Cam For Stock Heads


-Bigger is NOT always Better.
-Sound does NOT equal Power.
-Before selecting a cam you must develop your needs/wants/plans for your car, as that is what should determine which camshaft you select.
-Very basic understanding of a camshaft below; to better understand what the duration, lift, and lobe separation of a cam means, give this thread a look:
https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html

Ex: Stock 1997 F-Body Camshaft Specs: (200/207 .447/.459 117 LSA)

Duration: Duration is the time that the valve is open. Increasing the duration keeps the valves open longer which increases top-end power therefore raising the powerband.
Lift: Lift is the maximum amount in inches that the valves are open. More lift equals more horsepower and torque but at the same time high lift can lead to more peaky torque curves.
Lobe Separation: LSA is the number of degrees the intake and exhaust lobes are separated. The lower the LSA, the increased the overlap. Increasing overlap increases top-end power while reducing low-speed power and idle quality.

If you are in the market for a cam purely for sound and are willing to sacrifice usable power and drivability then something along the lines of the cc306 or GM847 will suite you well. However, if you want the full potential out of these cams you will need to be shifting at 6700-6800rpm which is VERY risky on the stock short block. A stock headed LT1 with a baby Crane 227 cam will 9 times out of 10 run better times than an equally setup stock headed LT1 with a large GM847 cam shifting at 6000rpm; different story if the car is shifting at 6700rpm however. Also just because camshafts as large as the cc306, GM847, etc. make more peak power, doesn't mean the car is faster. The key is usable power which is the power under the curve. Camshafts that large, lack low-end power because their powerbands are more geared towards higher rpm's, which is why a cam as large as they are not recommended for a stock headed setup. If you error on choosing a cam too small, you will still enjoy driving the car more than you did while it was stock and will be motivated to go a little bigger. Erroring on choosing too big of a cam will more than likely kill your enjoyment of driving the car compared to when it was stock therefore making it harder to be motivated to go smaller. Below are some of the most popular and proven off the-shelf camshafts that will work great with stock heads and perform well on the street and on the track. Along with the off the-shelf cams listed is the option to go with a custom grind which in most cases is the best overall option. Keep in mind, the advertised rpm range of a particular cam given by the manufacturer is not necessarily accurate and most cases it is not!


Custom Grind:

Pros: Optimal choice for most power and best drivability because the camshaft is ground specifically for your setup and what you want out of the car.
Cons: Cost a little more than an off the-shelf camshaft. If you change your setup down the road, the custom cam may not work to its potential on your new setup.
Pass Emissions?: N/A
Shift Point for Maximum Performance: N/A
Idle Characteristics: N/A
M6; Require Gears?: N/A
A4; Require Stall?: N/A


Comp Cams:

cc305: (220/230 .544/.544 114lsa) w/ 1.6RR's
Very similar in size to the LT4 Hot Cam but with 2 more degrees of duration on the intake and exhaust side at .050 and a bit more lift. Features a 114lsa giving the cam a wider powerband. The 114lsa over a 112lsa increases bottom-end power while decreasing top-end power. The 114lsa is sometimes favored by cars running Nitrous or Blowers because it provides less overlap than a 112lsa which helps maximize the power coming from the Nitrous or Blower. Features Comp's XE (Xtreme Energy) lobes for more top-end power.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6200rpm
Idle Characteristics: Smooth Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


cc503: (224/230 .535/.544 112lsa) w/ 1.6RR's
Widely known for being the biggest cam you want to run on a stock headed car without sacrificing usable power and drivability. Has a strong mid-range with good top-end power. Features Comp's XE (Xtreme Energy) lobes for more top-end power. Will have some cam surge.
Pass Emissions?: No, requires tuning to pass.
Shift Point for Maximum Performance: 6400-6500rpm
Idle Characteristics: Choppy Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


Crane Cams:

Crane 227: (210/224 .511/.553 112lsa) w/1.6RR's
Very good proven performer on stock heads. Stock LT1 heads have very restrictive exhaust ports relative to the intake ports. The 227's wide split in duration helps balance that out. The 227's low-end power starts low and is consistant through the entire mid-range. Known to be a torque monster with great drivability. Held a cam-only record for quite some time.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6100-6200rpm
Idle Characteristics: Smooth Idle with a Slight Lope
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


GMPP:

LT4 Hot Cam: (218/228 .525/.525 112lsa) w/ 1.6RR's
Good drivability with a decent midrange, step up up from the factory LT4 camshaft hence the "Hot" in LT4 "Hot Cam".
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6100-6300rpm
Idle Characteristics: Slighty Choppy Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


GM846 AKA Crane 109831: (222/230 .543/.563 112lsa) w/ 1.6RR's
Very similar to the cc503 just with 2 degrees less duration at .050 on the intake side and more lift on both the intake and exhaust side. Strong mid-range and good top-end power. Will have some cam surge.
Pass Emissions?: No, requires tuning.
Shift Point for Maximum Performance: 6300-6400rpm
Idle Characteristics: Choppy Idle
M6; Require Gears?: No
A4; Require Stall?: 2500+ Stall Speed


Lingenfelter Performance Engineering:

LPE 211/219: (211/219 .530/.560 112lsa) w/ 1.6RR's
Has great drivability and known to have instant torque in the low rpm's. Lope is not very noticible making it a nice sleeper cam.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6000-6100rpm
Idle Characteristics: Smooth Idle
M6; Require Gears?: No
A4; Require Stall?: 2600+ Stall Speed


LPE 219/219: (219/219 .560/.560 112lsa) w/ 1.6RR's
Known to be a great performing cam with awesome drivability. Quite torquey in the mid-range and top-end with a strong mid-range powerband.
Pass Emissions?: Yes
Shift Point for Maximum Performance: 6100-6200rpm
Idle Characteristics: Fair Idle with a Slight Lope
M6; Require Gears?: No
A4; Require Stall?: 2600+ Stall Speed





Part 2: The Components Needed For A Cam Swap

The following are the components that are required/recommended for a Cam Swap on stock heads. The valvetrain is not a good place to cut corners with. As most of you are working with a budget, it is recommended to do it right the first time, so it can all be done one time and one time only.

Bad_tx_Z28

iTrader: (3)

thats alot of good info..free bump

3pnt4maro

iTrader: (2)

I agree..wish i had something like this when i chose mine..you answered alot of the questions i had when i was a newbie

BlackShadowZ28

What is a safe RPM to spin a stock short block to?

3pnt4maro

iTrader: (2)

they say around 6200 is what i have heard..mine is set at 6200 for the limiter and my shifts at 6000 but mine pulls so damn hard all the way to redline i think it probably has more

StealthFormula

iTrader: (35)

I've heard around there too

I think its not so much a limit but based off of luck and condition of the motor. Some people have spun up to 6700/6800 for extended periods of time and have been fine while others have spun a bearing right off the bat. The lower RPM the better obviously and the lower mileage on the motor the better but many people wont go too far above 6000 because thats where spinning bearings etc. etc. have been proven to happen. Also stock 4l60e's die for two reasons 1.) Heat and 2.) High RPM's, so spinning it up real high can kill the trans too.

porksoda

iTrader: (39)

Good job Stealth! I've been wanting to write one of these up and try to get it stickied but I'm too busy with work and school.

95Lwind05

iTrader: (6)

excellent write up so far, thanks for doing it, i know i will be reading it!

jasonp31

Great write-up!! Thanks.

nomoneyz

iTrader: (15)

Bump!!! Good info. Makes me want a cam even more. Thanks.

grn95t/a

iTrader: (10)

makes me mad all over agian for buying the hot cam! lol!

96capricemgr

iTrader: (1)

One thing I think needs to be said with a beginners cam guide is ERROR ON THE SMALL SIDE. If you go too small you will still enjoy the car more than stock, but just want more. I have seen too many people go way too big and not enjoy the car anymore at which point it is hard for them to be motivated to spend the money and time to tame it a little. If you error too small and want to go bigger you are still interested and it is easier to just do it over and go a bit bigger.

StealthFormula

iTrader: (35)

I agree, I will incorporate that in there

StealthFormula

iTrader: (35)

to the top
any input, proposed corrections so far?

1bdbrd

iTrader: (12)

I don't agree with the hot cam being better than the cc306. Maybe if the rest of the car was setup correctly for the hot cam and the cc306 was the only mod but thats a given for any cam.

StealthFormula

iTrader: (35)

The example was given with a 6000rpm shiftpoint which many people do not want to exceed. No doubt that the a car with the cc306 or gm847 would out perform an equally setup car with the hot cam at say a 6500rpm+ shiftpoint.
the first post here helps clarify it http://web.camaross.com/forums/showt...imiter+nitrous

rasputin

iTrader: (3)

This is pretty good buddy, I really got to give it to ya. On LS1tech, there is so much info on LS1 cams, but nothing on LT1s, so this should be stickied and hopefully a lot of people will read it.

I like what I see, but it can obviously be better. My main concern is the two trains of though butting heads here which is of course the big cams versus the small cams relative to track times and dyno numbers. Its a shame we cannot statistically test all these different cams in controlled environments with perfect data to back up our tests, and then formulate conclusions based off of our data. Instead you kinda have to go off of what other people say using what little non scientific to little scientific data you have. Thats what always kept me away from doing something like this.

However you really nailed it when you said that these smaller cams will perform better than bigger cams when shifted below 6200RPM. I think that is the most critical part of this whole project and you should stress it as much as possible.

As far as the description of the cams, you should have some kind of list that you go off of when you describe them. Cams are so abstract so its hard to describe them, but when you answer certain points I think it becomes easier, especially when you answer specific questions that everyone wants to know. These include:

*low mid or high end power levels, or a combination
*shift points
*does it idle well or is it choppy, and what is the ideal rpm to set it at
*passing emissions
*is the lift high enough that I have to use a certain spring or does the cam require something special?
*tuning
*sound
*better for an M6 or an A4
*required stall RPM

Hopefully people can add to those but thats what I personally look for in a cam. I think if you answer those questions, you will have a very nice format, that is clear and easy to read.

Good luck and I will add more in later as your work progresses.

slick1851

I agree


Smaller isnt always better, and bigger isnt always better


You need to know what you want and your needs, I just have a problem with the post being a little anti large cam

slick1851

I think we really need to get away from these comon cams, I think its hurting the LT1 world by feeding us the same crap.


We need newer/Custom cams to LT1s needs


Not some out dated off the self stuff

Karl Ellwein

Stealth Formula, Lookin' Good!!

You were working on the supporting parts: How about something like my cut and paste below.

Part 2: The Components Needed For A Cam Swap

The following are the components that are required/recommended for a Cam Swap on stock heads. The valvetrain is not a good place to cut corners with. As most of you are working with a budget, it is recommended to do it right the first time, so it can all be done one time and one time only.

Pushrods:
Benefit of Upgrading: A stiffer pushrod helps to reduce pushrod "flex" and along with the valve springs helps to keep the valves under proper control and away from valve float and uncontrolled harmonics.
Required? No, but highly recommended.
Popular Choices: Chromoly 5/16" or 3/8" outside diameter. Hardend pushrods required if using guide plates.


Ever notice that all the Ai heads/cam packages come with 3/8" Chromoly pushrods? I learned about the importance of having a good stiff (non-spring-like) pushrod from a kid 1/2 my age, (Bret Bauer). A simple thing like that is often overlooked.

Valve springs:

I dont have specific suggestions as to what to say here other than maybe some mention that the valve spring is probably the most important part of the cam swap. High quality and properly set up valve springs are a must.

slick1851, I was getting ready to also post about "custom" cams and then during the typing of my post I see you posted, but in the opposite direction.

On the subject of custom cams designed for your specific application. Can a custom cam owner change the car mods and still keep the custom cam? That's a loaded question. (Sure, most of the time yes). But I give big thumbs up and great valve to the proven shelf cams like the GM 846 (Crane 109831) and Crane 104227. A shelf cam can be used in a broad range of combinations and preform exceptionally well. Many car owners enjoy changing their car combination more than a few times.

Karl Ellwein