back in '97 when i purchased my first cam,a bbc solid roller from ultradyne 251/260 .050 .630/.630 110,

i was under the impression that this cam and it's gentle nature of "street roller design" was the most cam you could run and put [real] miles on it.

.630 lift was pushing it as far as spring life,160/450 pressures were max for roller lifter life,now i am seeing "xtreme energy" and "pro street/oval track" rollers with close to .700 lift being used on the street,with greater intensity.

what is the limit for a truly driven ride???
don't want to pound valve seats to death,not to mention kill roller lifters. thanx

Eric,

That family of cams has been used as daily drivers for about 23 years now. It is the same family as my 24-Hours of LeMans cams(SB290/300R8, 254/264 at .050, .556/.556 valve lift, 108 LSA).
I consider this family to be 'Moderate' in opening/closing velocities, and peak acceleration rates. I actually have softer designs that are HUGE, like the BB328/350R16, 292/314 at .050, .825/.825 valve lift, and 116 LSA.
A lot of the BBC .710 lift families are just as soft as the .556/.630 family, but with more valve lift. Others, such as the SB288/296R6, are much more aggressive.
A cam like the 288/296R6 can be driven on the street if you keep an eye on things, but speaking purely mathematically, more aggressive cams ARE HARDER on parts. Pure physics......
You can open a valve MUCH harder than you close it, after all, opening is only pushing against the valve train, which is designed to MOVE! Closing the valve hard lets it meet the valve seat, which is not designed to move. Slamming into the valve seat also creates those pesky little valve train noises. Running high seat loads to counter high closing rates just helps batter things up.
I'm not going to get into the "I can close the valve faster than YOU!" game......
If this doesn't answer you exactly, let me know what you want....

UDHarold

thanx harold,what are the specs on the 288/296r6,and how much more power over my cam can i expect on a pump gas 502???

what spring pressures are needed???

thanx

Eric,

I generally make the 288/296R6 as a small-block cam, but I have made a few BB288/296R9s, 257/265 at .050(BBC growth--), .710/.710 valve lift, 109 LSA. The valve timing at .020 is IVO 39° BTDC IVC 69° ABDC EVO 81° BBDC EVC 35° ATDC. This cam is extremely streetable with a 3000 SS converter and a 3.90 rear, even at 3700 lbs. We're talking 210 lbs on the seat, 525 lbs open.
A lighter car, 4000 SS, 4.56s, puts the car well in the 10s, N/A.
I would estimate a 50 BHP difference between your cam and the 288/296R.
I also make another 290/300R, the same at .050 as your cam, but with .710/.710 valve lift. It is about 2° smaller at .200 than the 288/296R.
Your cam and the high-lift 290/300R both have 36° Major Intensity, .020 to .050, and both familiies of cams have done extremely well in 24-hour racing, LeMans and Daytona.
The 288/296R has 33° Major Intensity.

UDHarold

Harold,

Would this camshaft be a good replacement for my Crane 169621 (230/236, .598/.610, 114° LC)? I am looking to move away from the HR in the Mercury Racing HP500 EFI in the Camaro. Seems to bump the DCR significantly.

Thanks
James
www.adivanman.com (http://www.adivanman.com)