Harold please advise. I'm looking for a new cam, more low end torque starting @1000. Right now I'm running a compXE 282-S, 454 4 bolt, LS-6 replacement pistons(the low dome one's), GMPP signature series aluminum heads(12363390)with 2.25 intakes/290cc runners, Weiand Stealth intake and Holley 830 carb. Running thru stock Corvette manifolds to a stock Corvette side exhaust. Eventually would like to add a set of Hooker side-mounts. Rear end is currently a 3:36 with a M-22 tranny, but may change that too, maybe a 3:73 or 4:11's. NOT looking for top end.

Car won't see much strip action, but I'd like some rumpty-rump and don't like getting beat at red lights. Mostly a street cruiser.

The Compcams 282S-S starts coming on strong around 2,500.

Hyd or solid (or both) or even a roller if you have one that'd work with my GMPP springs.

Thanks
Len

Len,

Have to check on the springs, will reply later today...

UDHarold

Len, just curious 'cause I'm running the same heads on the 498. Your Stealth is oval or rect? I used the GMPP roval intake. Tony

Originally posted by chevywidow:
Len, just curious 'cause I'm running the same heads on the 498. Your Stealth is oval or rect? I used the GMPP roval intake. Tony Stealth & heads are both oval.

Oh, and Harold, I have no brand loyaly and won't hold it against you if it's one of the new Voo-doo's. http://forums.corvetteforum.com/images/smilies/smilielol5.gif ;) http://www.corvetteactioncenter.com/forums/images/smilies/gap.gif

I wonder if Lunati/Holley is going to advertise VOO DOO during the NHRA races, seems like they could have come up with a little better name.

:D

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Jughead,

If those are the L2399 pistons and depending on if the block is decked or not and what head gasket you have, the CR of that motor is down in the 9.0 - 9.2 range, probably not much more. My guess is the low CR is compounding the lazy bottum end of the cam and aggravated by the close ratios box w/ 3.36 gears. Before I would change it all out, consider advancing the cam to maybe 104ICL (or at least make sure it is no less than 106ICL) and open up the lash, especially on the intakes. A gear change to 3.73+ will make up the difference in a hurry.

Just curious, have you ran a compression test to determine cylinder pressure? What is the engine vac at idle with the current setup?.

For comparison, I just changed out the flat tappet hyd cam Crane 286 Powermax( 286/296, 226/236 on 112LSA, installed at 110ICL) to a Comp NX279HR (279/294, 230/242 on 113LSA installed at 108ICL). The motor went from a lopey idle at 900 with 11 - 12" vac to 950 idle with a crisp yet lopey idle and about 13" vac. The seat specs are really not that much different between the two. The improvement in idle quality has to be the additional cam advance and the slightly wider lobe sep. Big assumption here, but along with the improved vac. at idle, I would expect a nice gain in bottum end power as well.

Originally posted by GRN69CHV:
Jughead,

If those are the L2399 pistons and depending on if the block is decked or not and what head gasket you have, the CR of that motor is down in the 9.0 - 9.2 range, probably not much more. My guess is the low CR is compounding the lazy bottum end of the cam and aggravated by the close ratios box w/ 3.36 gears. Before I would change it all out, consider advancing the cam to maybe 104ICL (or at least make sure it is no less than 106ICL) and open up the lash, especially on the intakes. A gear change to 3.73+ will make up the difference in a hurry.

Just curious, have you ran a compression test to determine cylinder pressure? What is the engine vac at idle with the current setup?.

For comparison, I just changed out the flat tappet hyd cam Crane 286 Powermax( 286/296, 226/236 on 112LSA, installed at 110ICL) to a Comp NX279HR (279/294, 230/242 on 113LSA installed at 108ICL). The motor went from a lopey idle at 900 with 11 - 12" vac to 950 idle with a crisp yet lopey idle and about 13" vac. The seat specs are really not that much different between the two. The improvement in idle quality has to be the additional cam advance and the slightly wider lobe sep. Big assumption here, but along with the improved vac. at idle, I would expect a nice gain in bottum end power as well. Not sure what 104ICL means?

No, didn't run a compression test yet. Vacuum @900 was 15.

Have you played with the timing? Do you run manifold vaccum for the vaccum advance or ported vaccum source?

Originally posted by GRN69CHV:
Have you played with the timing? Do you run manifold vaccum for the vaccum advance or ported vaccum source? Timing I had initially set @18, but then somebody said to change it to 14max.

I'm running the vac advance from the base of the carb since there's no port in the carb itself.

Far from an expert here, but two things I can input. First with 15" vac at idle, the motor should have plenty of bottum end, if you told me 10-11", I could see a lack of bottum end power. Second, I think you need to address your timing and mechanical advance. Nowadays, almost no one that I know sets their timing by initial. Best way is to mark your balancer for 38 degrees (strike a line on the balancer at 2.65" ahead of the timing mark). With the vac advance disconnected, rev the engine to about 3000 RPM (or whatever you need for full mech advance) and set the timing to 38 degrees. Idle it down and check the initial for future reference. Make sure you have a timing curve that gets the full mech advance in by 2800 while you are at it. Last, you can always check the cam specs and lash the cam with the max recommended lash to effectively shorten it.

I would do these things first before ripping into the motor, especially in a Vette. I have changed cams in a small block with the motor still in the Vette and had to practically disassemble what seemed like half the front end, I couldn't imagine doing this with the big block.

By the way, I ran the CR finally and it is probably closer to 9.5/1.

If you do go to a swap, a camthat starts pulling at 1000? Man,you don't need anything Harold engineered. Go to CompProducts and get yourself a GMt takeout roller. Cheap. All low end.

I am curious, do you want the same or more power than the 282S, and the 1000 RPM start range?
That will be a hard one to do, as generally cams that work over the 1000-5000 range do not work that good at 6000. And good vacuum and rumpty-rump are generally opposites, also.

UDHarold

Originally posted by UDHarold:
I am curious, do you want the same or more power than the 282S, and the 1000 RPM start range?
That will be a hard one to do, as generally cams that work over the 1000-5000 range do not work that good at 6000. And good vacuum and rumpty-rump are generally opposites, also.

UDHarold Thanks.
I guess 1000 is a little low aas Gene pointed out. I want to be smokin' by 2000-2500 and don't care if it has nothing at 6000. No, I don't expect the cam to out perform the 282 at the top.

I'm not overly concerned about vacuum. The only thing I have running off vacuum is the pop-up headlights. Brakes are not power.

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Something along the lines of the old 280/88 hydraulic, which in today's terms are the 60202,or 60203 VooDoo cams. Soundslike the 262, or 60202 is more correct here than the 268 duration.

http://www.holley.com/HiOctn/ProdLine/Products/IEC/IECC/Voodoo.html

Hey Harold, I'd like to have a few 268 VooDoo's for our CanAm show giveaways( sbc and bbc ). Who do I call? Show banners would be nice,etc.

ttt.
Any more imput.

Thanks
Terry

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you don't need a cam change at all. you need a gear change, either in the rear end or the trans. you have a 2.20 first gear in your trans with a 336 in the rear makes for a dead take off. I would leave the rear gear and put a borg warner st-10 with either a 264 or 288 first gear. other option is 3.73 gears or 3.90. do both these and you'll think you have a new car. don't swap the cam as you will not really change anything but your pocket will be lighter. that cam should kick booty it just needs gearing.

427L88,

You need to talk to Jay Adams, he is the Sales Manager/New Products Co-ordinator. Make sure you tell him I told you to call, and ask him to get me in the room.....
I would love to work with you on this.

UDHarold

has anybody recommended a 3000 stall yet????
shane

Originally posted by ovelle:
has anybody recommended a 3000 stall yet????
shane It's a 4sp.

:D

Unlimited Stall!

Harold, thank you. I might even try on Monday.