The 454/496 is sitting on the stand in a state of suspended animation, or so it seems. I am probably not going to get around to finishing it until later in the year, I just don't have the time or ambition right now to change everything in the car to make it work [exhaust, converter, suspension]. In the interim I want to throw a hyd roller in the 408. Eventually, the 408 will get stored in the garage - my son has already claimed it for a Camaro project he wants to do - we'll see. I already have a new set of lifters and a set of 925 springs (in fact I already installed the springs). I just need to settle on a cam.

Here's a highlight on the details and some cams I am looking at.

408 BBC
290 ovals 2.19/1.72's
9.6 - 9.7 CR
Performer 2-0 w/ 770 Holley
1.75 headers into 2.5" dual exh.
3000 stall, 3.73's

Keep in mind I am looking for the most power between 3000 - 6000 rpm. Below this doesn't really matter much, as long it pulls about 10 - 11" vacuum for the brakes, above 6K, well being realistic, valve float is inevitable . If you guys have used any of these or something similiar, please let me know. (Note: I want to keep the lift to about .600 or less, otherwise I will have to get into too much changeout).

Comp:
290HR 290/290 232/232 .578/.578 110LSA
XR282HR 282/288 230/236 .510/.520 110LSA
XR288HR 288/294 236/242 .527/.540 110LSA
XM284HR 284/290 230/236 .547/.547 112LSA
NX279HR 279/294 230/242 .534/.545 113LSA (I like the extra exhaust duration on this, just not sure about the lift intensity here - it seems real severe on the intake side, maybe not)

Crower:
01402 278/286 222/229 .54/.56 110LSA (This may actually work, but is probably a little small for what I want)
01403 287/296 229/236 .56/.58 110LSA

Crane:
HR288 288/296 226/234 .587/.610 112LSA (this may work, but the .610 will be close to retainer / guide interference)

There are also quite a few Lunati grinds, but most if not all are 112-114 LSA and 110 - 112 ICL. I was really leaning to an ICL of 106 - 108 to keep the cylinder pressure up. I tend to think the later intake closing in a hyd roller design will make for a very lazy bottum end.

I'd like to see what the reccomendations are for this as well. I have wished I would have gone hyd roller in my 489 when I had it apart last time.

I'm sure UD Harold at Lunati can grind you exactly what you want or make some killer reccomendations.

I was surprised I didn't get any input, but my take is that a lot of Chevelle owners are traditionalists or hard core racers, neither of which fit the mold for hyd rollers. Basically, I just wanted to use up the MrkIV parts I already have in the 408 for a while before I take it out later this year for the bigger motor. But that is another story.

I started to disconnect the 408 motor in the car for removal and didn't get past the removal of the distributor, radiator, power steering pump and alternator when it hit me that I should just do the cam change I had been sitting off/on for some time, at least it would give me a "real" comparison of what the impact is between flat tappet hyd and hyd roller. Depending on the result will direct me to how to finally setup the GenVI block on the stand - or so I would think.

PS - Going out on a limb here - I ordered the NX279HR. It follows real close to the cam that another member is running (have to do a search for his name later - Penna guy, lives in Collegeville - actually not too far from me ), but he is running a 402 with a solid roller with similiar specs - 113LSA, 108 ICL, very similiar durations, but of course solid roller with the applicable lift - the car runs 11.90's. I have this gut feeling that the key to the smaller motors may be to get as broad of a torque curve as possible so the motor doesn't fall out of the powerband in between shifts. If I could get the broad powerband of my 327CI 5.3L Vortec pickup, but in the 408CI big block, I would be real content.

I'm using something similar. Custom gorund comp cams hydraulic roller:

224/230 duration @050
0.573/0.585 lift with 1.72 rockers (Comp roller tip).
114 LSA (measured 115.25)
4 degrees adv (measured 5)

Engine is a 454. 1 7/8" headers. Edelbrock heads. Port EFI.

Smooth idle. Pulls 19" vacuum @ 850 rpm. Power range 800 rpm to 6k. Peak hp 5300 rpm.

Based on this I'd say the cams you list around 230 intake duration should give you more than 11" of vacuum even with the tighter LSA and less cubic inches.

Also, I wouldn't worry too much about lazy bottom end. I realize you have less cubes, but mine pulls strong all the way from idle with alot of LSA and not much compression. I'm only at 9.5:1 and it actually runs on 89 octane with no fuss.

Zwede, whose lifters/springs are you using?

GRN69, the cam you ordered is a nitrous or blower grind. Is that what you wanted?

I am going to use the XR276HR in my 10:1 427. My goal is a very strong cruising motor.

TJC: I'm using comps retrofit lifters and pushrods. The springs are the ones that came with the Edelbrock heads.

Zwede, are they the Magnum lifters, or the standard retros?? tnx.

Didn't even know there were two of them. Back when I got them I think there was only one choice; the 854's which they now call "high energy". I've been running them for 4 years now, about 30k miles.

Yup, the magnums are supposed to be anti pump up. I have the standards as well. Good to hear that it has lasted so well. thanks.

TJC,

Yes it is a N20/ blower grind. I was mainly interested in the extra exhaust duration and the wider LSA to control overlap. I wanted to keep the .050 overlap to a max of 10 degrees. A lot of the rollers I have looked at are 112 - 114LSA. This cam is wide for something from Comp, but actually has a narrower LSA than most of the Lunati cams which are mostly 114. The exhaust lobe is their standard 294 Extreme Roller Lobe - same lobe from the XR288HR and the intake is a quick opening ramp lobe that I think is based on one of the cheater rule profiles. I had looked into this prior. Yes, a tighter lobe profile would be more potent in the midrange, but I am looking for a broad torque band. Keep in mind, I am running a ported set of oval ports with 2.19 intakes and stock size 1.72's in the exhaust. I know guys run this combo, but in retrospect, I think I have created a mismatched flow profile. If I had to do it again, I would be inclined to concentrate all efforts on the exhaust, stock valve sizes in both or only upgrade the size in the exhaust and then run a fat single pattern. I am running dual pattern flat tappet hydraulic, but the roller profiles should really wake this up. Like I said earlier, I am going out on a limb here to test a theory. I already had the lifters and pushrods, so I am only out the price of a cam at this point. The next motor is GenVI based, already tried the lifters in it with a .610lift GenVI cam I have and the tie bars just barely clear the tops of the lifter bosses - short of grinding on them (something I don't intend to do on a new block) I would not consider running them. But I should be able to sort out a few things that I need to address on the car with this motor for now.

Grn69CHV,
I am that guy in Collegeville.
I run a small Comp solid roller in my 410BBC.
specs are 236/248 @.050, 273/285 @ .015
LSA is 113, 108 ICL. 12 degree split
It pulls about 13"HG at Idle.
I run an overdrive with a tight lockup converter
and believe the wide LSA provides a better avg torque. Helps me get through the RPM drop on the 1-2 shift on the 700r4.
rear gears are 3.73 with a 26" tire.
I run an RPM airgap with 750DP and 1 inch spacer.
The heads are large oval truck castings(136's) with 2.19
and 1.72 valves.
The car weighs 3880 with me in it.
Runs consistent mid 113mph trap speeds
Et's depend on traction has gone 11.92 @ 114.01.
Since your so close your welcome to come by and
check it out.
Dave Mizell

Dave,

Couldn't remember your sig. earlier today when I posted but I had seen your info and thought I would mimic your set up. I know a hyr roller is not on par with a solid, and this cam is not as potent as yours, but I when I looked at it in a different light, the addtional spread of intake to exhaust and the wider LSA made sense. Tough to argue with a proven package! If this works out like I think, the GenVI motor is going to take a different direction than originally planned.
Hey, we might start a trend of wide LSA smooth idling cruisers :cool:

Grn69CHV,
The cam you selected is as close to my solid as you can get with a HYD roller.
Your HYD is rated at .006 279/294
I'm at .015 273/285, same LSA/ICL
My car Idles smoothly, people think its just a stock 396 with headers/intake. Sounds different when you open it up.
A friend of mine has a C5 and we did the stoplight grand prix. He could not believe what my car sounded like at WOT. Actually scared him.
I'm all for the Jekyll/Hyde theme.
Let me know how your combo turns out. Maybe we could meet at the track/dyno or cruise sometime.
Thanks,
DaveM

I wasn't so sure if 230@.050 would have much below 3000 in a 408CI motor, but it's really not much of an issue with the converter I have anyway. Unless something gets terribly in the way, I should have it in there on Saturday.

Dave, Have you been to Chesterbrook Cruise Nights? That's about as far North as I had been on a regular basis for cruise nights. Usually I have stayed around West Chester area and the rare trip to Kahunaville in Wilm., Del..

I went to Chesterbrook once this year.
Let me know if your going in the spring. They are on the 4th Saturday starting in April.
My car is a Green '71.
Dave M

Joe,

Have you ever seen that all blue hard top '69 driving around here once in while?

I wonder if that person is on TC.

Vince, How's it going?
Don't know, I have never noticed any other locals post. There are a couple of blue 69's around here though. One of them is a long time friend of mine - Steven. He's running a 69 with a ZZ502, recently put a 6-71 on it. But it's pretty much just a drive around the block car now. Mostly he just takes it to the Friday Night sessions in season.

By the way for you fellow TC'rs, turns out Vince and I may hold the record for living the closest. Literally, it's 1 country mile.

Dave,
I didn't get to Chesterbrook with my car until later in the season last year, I still had it apart. May not make the early part of the season with the car this year also - car is going to be stripped and repainted in April - May. But I will probably get there anyway, at any given time there's 6 other cars in the driveway and one of them is bound to be clean and have gas in the tank.

Vince,
My younger Brother lives in Pike Creek. He has an all blue '72 with rally wheels. He brings his car to my place to work on it. He runs a 383
mid 12's on the motor high 11.50's with 100 shot.
His car is very much stock appearing like mine.
He is always running around that northern Del. area.
He just loves his Lunati solid cam.
Dave M

The one I'm talking about is a 69 all-blue w/a fair quality paint job. Mostly see him driving on US1 and US202.

I put my Chevelle away for now since the road has been salted. Spinning wheels + road salt/rocks = many chips on 1/4 panels!