:confused:I am building a 454 .60 over 4.25 stroke 6.385 rods = 496. I am looking for 10.1 compression. I am using 049 heads decked at shop and ported at home not at a shop. I will be running 2.19 1.88 valves. The block will be 0 deck with either flat top with valve relief or 18cc dome pistons depending on my combination to reach 10.1. The reason I cant decide is I need to cc my heads to be sure the cc of the heads. I will lose 3 cc per chamber for decking. I will use .39 gasket or larger but not large enough to hurt the quench. This will be in a 71 SS Chevelle with 400 turbo and 12 bolt 3.56 or 3.31 posi (4.11 in car right now). I will drive on the street 98 pecent of the time.

Here is the cam I am thinking of going with: Comp cam #11-771-8
.242/.248 .646/.653 @ .50 110LS

I would like to know if this is too much cam or not? Am I going to have vacume problems? How often will I have to set valves? Will this lift cause me more problems than worth it? Thanks JP

^ cam will be fine, but do yourself a very big favor and get it on a billet core instead of cast. Cast for SR cams are counter-productive, because you can't run enough spring pressure to be adequate and, if you do, you'll whipe the cam. With comp cam, -8 is a cast and -9 is billet. You might need to call them to order it, but it's worth the extra 50 bucks (if that)

A little on the small side to me. The Lunati equivilent specs out for a 396-427. I would step it up one notch -
Lunati 60233
Advertised Duration (Int/Exh): 279/285
Duration @ .050 (Int/Exh): 249/255
Gross Valve Lift (Int/Exh): .663/.685
LSA/ICL: 110/106
Valve Lash (Int/Exh): .018/.018
RPM Range: 2800-7000

Used that cam in a 496 and a 511 4.311 bore x 4.375 stroke works great.

Used that cam in a 496 and a 511 4.311 bore x 4.375 stroke works great.

Since I have 10.5-1 compression, I went another notch up.

Lunati 60234
Advertised Duration (Int/Exh): 285/293
Duration @ .050 (Int/Exh): 255/263
Gross Valve Lift (Int/Exh): .680/.680
LSA/ICL: 110/106
Valve Lash (Int/Exh): .018/.018
RPM Range: 3000-7200

Here is the cam I am thinking of going with: Comp cam #11-771-8
.242/.248 .646/.653 @ .50 110LS


I would not use that cam. The -8 in the part number means the cam was ground on a "cast core" instead of a billet core. Not good.

Read through the attached thread and you will see why not to use a cast core with a solid roller.

http://www.chevelles.com/forums/show...22comp+cams%22

I've been running the Comp Cams Cast Core SR CB 288AR-10 for the last couple of years with the 933 springs 200 on the seat and 500 open in my 460 BBC without problems. The Lash has not flinched in that time. HIPPO Lifters, a strong Anti-Cam Walk Device and a Stud Girdle is critical. I run a Donovan Cam Gear drive which locks the cam in solid with a .004" end play. 6500 rpm is not a problem but if you want 7000 you will require a billet cam and run higher spring pressures. When I get around to it I might consider a Billet 112 LSA grind with a Marine Profile and run something like the 927's but then you risk pounding the seats for a daily driver.

Skeeter55 just finished a very similar build over at Team Camaro, you might be interested in the thread:http://www.camaros.net/forums/showthread.php?t=148682
(http://www.camaros.net/forums/showthread.php?t=148682)

^ you're not going to pound the seats with high spring pressure, as the lifter will stay on the cam and follow it, and cams have a designed area on the closing side of the lobe that slows down the valve right before it closes so that you don't pound the seat. Now, if you don't have enough pressure and the lifter can't follow the closing ramp, then you certainly will pound it, or explode a lifter over time.
It's almost worst not to have enough than it is to have a tad too much. my XR296 lived

Aside for the -8 discussion, the 242/248 will be very mild in a 496. That cam is even smaller than it appears after you consider lash needs to be backed out. I ran a 245/252 in a 454 (HR - no lash)...and it was pretty good. I would go at least to the XR286 or the 60233 Voodoo.

I have had more people suggest I go with the XR286R cam over the XR280R. I am concerned this maybe too much cam for this car for the street? Why do you all suggest this over the XR280R? I dont plan to go over 6500 RPM and this cam range is 3000 to 7000. I am also comfused if I should go with the -9 billet over the -8 cast core? Thanks JP

The XR286 is a better choice, here's a good read for you. http://www.compcams.com/Community/Articles/Details.asp?ID=-2023343081

Does the XR286 cam idle OK or is it really radical?

Does the XR286 cam idle OK or is it really radical?...and is it going to drive well with a 3.31 gear?

Guys remember this guy isnt racing this, hes driving it on the street 98 percent of the time. That means braking, traffic and highway gear ratio's. Go for a hyd roller, less to worry about and get a cam in the low to mid .600 lift range.