trilkb

iTrader: (4)

I said this in the beginning of buying my camshaft due to its high lift numbers, I have stock heads right now as well, that i would do 1.6 rocker arms but would always keep 1.5's in mind incase of any issues.

With 1.6 rocker arms my lift is .606/.603.

Im running patriot 8401 spring kit, arp studs, chromemoly rods, Comp ultra pro mag 1.6 rockers. I havent had any issues yet with this setup.

With 1.5 rockers my lift would drop to .568/.565.

the duration of the cam on the cam card says with 1.6 its 226/232 and with 1.5's its 224/230, no idea how it changes but thats what the cam card says. Its not a very big duration cam.

The car runs good, however she has some "driveability" issues. Ive sat in traffic with her and dont have problems, but it just doesnt seem as friendly as my cc306 was, yet its a smaller cam. Im wondering if the 600+ lift and stock heads has anything to do with it, i dont think stock lt1 heads have great flow rate at 600 lift. According to some bench flow rates the intake starts to restrict from .500 to .600. Who knows if 5-10 cfm is anything to care about or not.

Trying to get opinions of people who can give me some insight if .568/.565 lift would be more suited for stock heads then the .606/.603 or if it would just be a waste of money to drop to the 1.5's. When i was looking for a cam some people said i was over thinking the small differences in lift, thats why im wondering if it will change much at all.

Thanks for reading!

EDIT: i also notice alot of the aftermarket camshafts in this duration range are .550-.570 lift with 1.6 rockers, and are often put into a "large" daily driver camshaft.

RamAir95TA

iTrader: (2)

I also doubt that the added lift is causing that much noticeable difference in drivability. I would suspect the tune more than anything.

trilkb

iTrader: (4)

its a pcmforless tune. I might be expecting a little much out of it.

Most people dont do a 600 lift cam so that was why i was curious if dropping the lift would help.

hopefully some other knowledgable people will voice an opinion too.

draggin97s10

iTrader: (2)

Ive ran 3 .612 lift cams. No driveability issues

trilkb

iTrader: (4)

stock heads on those .612 lift cams?

draggin97s10

iTrader: (2)

not it wasnt. LE2's sorry i didnt see stock heads.

1963SS

I'm pretty sure there is no advantage to having .600 lift on stock heads. Most flow charts that I've seen show the heads flowing less at .600 than they do at .500. So, although the valve is opening more the flow is actually less. You would probably pick up horsepower by going to a cam with lift in the .500 range. Since I believe that to be true it makes sense that the 1.5's would probably make marginally more power than the 1.6's.

Also, there's a reason people have driveability issues with big cams and stock heads. I'm assuming that you just want the big cam sound and not performance....right. There would be no other reason to use that cam on a stock set of heads.

Airflow calculators put the max horsepower with 200CFM heads at .600 at 365 HP@ 5900.

The same program puts the max horsepower with 212 CFM heads at .500 at 388@6250.

It looks to be a 23 horsepower gain by going with a smaller .500 cam that is matched to your heads airflow.

trilkb

iTrader: (4)

exactly what i was getting at with my first post. I noticed from .500 to .600 some restrictions. Im not singling out AI here but they have a 226/230 .560/.555, a 220/230 .560/.555 and a 226/234 .566/.566. Then i look at LE, very very similar cams, with very very close durations and lift numbers. Of course the way they get to the lift has alot to do with it, but in the end they are all staying in the .550-.570 range. Both of these guys have been grinding cams for awhile, so i would assume they know what a stock lt1 head flows at these lift numbers, and the fact they are targeting them says something to me.

Also this cam isnt a massive cam, its just high lift. I went with it because i was told by the man who ground it that it would make power similar to the CC306, only at lower rpms. The 600 lift was just to be "different". I figured if it didnt work i could always drop to the 1.5's. Its working, but im just wondering how well.

Looking at stock flow charts i was thinking i would gain something but im not sure what. 12cfm increase and 23hp...thats pretty significant.

I like the way you think!

wrd1972

iTrader: (12)

Higher lift lobes almost alway mean faster ramp rates which can lead to valve float and valve bounce issues. I once had a cam that had similar lift as yours and the power fell like a rock at 6K RPM due to these dangerous conditions. These conditions can be corrected with very strong springs to ensure that the lifter maintains continuous contact with the cam lobes but at the possible expense of overall valvetrain reliability. In general, higher lift lobes beat the valvetrain up more and ideal components become more essential.

Are you running the old LE1.5 cam? Sounds like you might be. Thats the cam I used to have and fought valvetrain control issues till I pulled it for a slightly lower lift, more stable cam.

But to answer the question, stock heads, I would run the 1.5 rockers for better reliability.

quik95lt1

iTrader: (7)

chances are you have a tune issue..........im running a .600 lift cam in my LS2 and its my daily driver.......runs perfectly fine.......no bucking idles great...........i wouldn't be afraid of the lift.........work on the tune instead........

trilkb

iTrader: (4)

I think you might've pm'd me way back when i first got the cam off another member, he had a Impala, dont think he ever ran it but bought it off someone who ran it for not long at all, might've been you. I honestly forget the guys name. I emailed him once it was running. Mike something? But yea the back of the cam says LE-HL-N20.

Anyways the patriot 8401's seem to be taking the abuse. In all honesty i havent pulled a valve cover off to check them out in a couple hundred miles, i should probably do that. I went with all top notch parts, and was told to stay away from beehive springs, i think i heard you were running them? I noticed a small power loss but i figured it was from going to a 2.75" flowmaster cat back instead of a dumped 3" y pipe lol. Seems to run and idle the same way it did when it first got fired up though.

trilkb

iTrader: (4)

quick95lt1...I know you know what your talking about...wouldnt doubt you, But you just put a stock lt1 head in the same catagory as a LS2 head....are you suuuure you want to stick to that statement? haha

The tune im sure needs help. I will just have to suck it up and get a wideband (just in time for winter!)

Car definetly has power...its just those low rpm's in overdrive that it doesnt care for. Ive been trying to look at tuning since i have the software to do it, but finding what to adjust is another story! I guess i had an idea that if i lowered the lift, i would possibly gain some driveability, and with stock lt1 heads...possibly power too.

kinglt-1

iTrader: (26)

the lift has nothing to do with drvieability... dropping to the 1.5's will put your lift figures back in the efficiency range of the stock heads, but its not goin to do a damn thing for driveability. You need a different tune, or something else is amiss.

trilkb

iTrader: (4)

king lt1 - agreed, thanks for the input. Im welcoming all of it. Efficency is the most important part, it might be worth it to change.

Its not like its a horror/nightmare to drive, i could just about kill someone everytime im in a 55mph zone tho, and i dont feel that this cam should have those characteristics. Its either cam or tune related, that much is forsure. Id just rather it not be a .606/.603 lift issue when that can be fixed fairly easy lol.

Anyone else run a cam in that duration? 224-230~ish? Any input on 2000rpm cruises?

BIGCAT7274

what is the intake center line and lobe separation angle for both cams? if you advance your cam 4* it may behave a little better but it will shift the peak power down a hair. probably 150 to 200 rpm.

ahritchie

iTrader: (1)

I had a smaller cam than that (lunati voodoo 60121 219/229) in a 6sp car that was drove just fine at 1800 RPM on a 70mph highway cruise in 6th gear, a little driveability loss from stock (PCM for less tune), it just didn't like slow speed parking lot maneuvers. After upgrading to 4.10 gears and getting a dyno tune it has more driveability than ever...it will pull from 2000rpm in 6th with no problem, way better than stock. I'm not sure which helped the most (probably just the 4.10's) or the dyno tune itself. What gears are you running? FYI...a good dyno tuner will pick up power and driveability over a mail order tune.

trilkb

iTrader: (4)

I have a 3.23 rear end. Ive deceided against the dyno tune, Its 600$ that i dont feel is worth it. I want to learn to tune this car, a ~175$ wideband should make that easier. I was quoted dyno tunes by 2 shops, one 600$, the other 750$. Im actually not a fan of speed shops. I dont trust them at all and have had bad experiences. Im not trying to complain about the tune and then say im not going to tune it, just saying...the car wont get dyno tuned because i want to get a larger understanding of tuning, and i have the tools to do so.

Its actually 1 cam, like i said i dont know why it has 2 durations on it, one with 1.6rr and one with 1.5rr.

Intake centerline is 108.00

Lsa is also 108

Overlap is 64.5 which puts it right inbetween a cc503 and cc306 cam (as far as overlap goes)

I put the cam in dot to dot.

Appreciate all the info so far!

BIGCAT7274

the reason there are 2 different duration numbers is rocker ratio affects both the lift and duration. i think the lsa is kinda tight for a street car cam. a cam with a 110 or 112 would behave better. also as for tuning don't be to afraid to throw some timing at. to little time will also cause poor drive ability.

trilkb

iTrader: (4)

the car is a weekender. It got drivin to work maybe twice last year, and it ran all summer. Its supposed to be more of a track car then street.

I see alot of people are saying that 1.5 rockers would put me in a lift range better suited for stock lt1 heads. Im thinking i may need to do that.

nitrous2fast

iTrader: (2)

Why don't you just pull the heads and have them ported??? put the money that you would from the new rockers into porting costs??