lift is the ability to make power. Duration is the ability to sustain power at a given rpm. Moderate lift and short duration cams paired with good flowing heads make for very nice broad powerbands.

 

What would be hi lift or short duration?

My HR might be 227/232 dur, .528"/535" lift @ 110

What do ya think?

I don't think it's that big of a cam.

It works pretty good tho with my 10:1, 355 with comp ptd 195 AFR's. :yes:

 

Depends on what "high lift" means. I asked a cam designer that question and he doesnt recommend it as it would give a peakier powerband and instability issues as the acceleration rates would have to be much higher.

 

well... i run a Lunati Voodo 101 w/ 1.6 rockers in a 327 3:55 posi gears & 700R4 and she is lively...

 

what are the cam specs for the Crower and Comp?

 

The Crower 00471is 286/292, 236/240@ .050" .555/.559" lift, LSA 110
and Comp 12-433-8 is 288/294, 236/242@ .050" .520/.540" lift, LSA 110, ICL 106

 

The Crower 00471is 286/292, 236/240@ .050" .555/.559" lift, LSA 110
and Comp 12-433-8 is 288/294, 236/242@ .050" .520/.540" lift, LSA 110, ICL 106

you pretty much just described my motor. mine is zero decked and shaved the 195's a bit to put it at 10.75:1 compression. the comp cam you listed is the same one I have. 750hp and an air gap. lots of other details in the setup, but it runs surprisingly strong off idle up to about 6500. this combo is a little radical for some people's tastes on the street, and would take some stall converter for sure if you run an automatic, but works real well with my TKO600. runs just fine on 91 octane with 36* total mechanical (no vac on my setup). you will need a vac can for power brakes... ask me how I know that. it does make for a pretty stout sbc though.

 

I don't think you're talking about enough difference in those numbers to really matter. Now if the rest of the lobe looks a lot different and creates much larger .200,.300. 400 etc duration numbers you could see some difference. That's why you really need ALL the lobe info to tell anything. Hard to get it though without a cam doctor type report.

When I think high lift on a smallblock I'm thinking at least .600" and .700" on a big block.

JIM

 

Look up some of the engine masters competitions. The trend for quite a while has been mild duration and very high lift. These engines make very good power, but also a broad torque curve.

I'd like to see some of the winning engines in a proven cars to see how they perform under real world on track conditions.

 

Hardest thing about that combo of cam properties, is the acceleration that the valve train experiences.

That, in addition to the usual duration and such, acts as a practical limit to the RPM range of a cam. The parts can only withstand a certain amount of beating. Which is why if you go to somebody's lobe catalog that lists "high RPM" lobes separately from others, the ramps are usually alot less violent: longer duration for any given amount of lift.

Making the most power on a couple of dyno pulls is one thing; surviving a hundred thousand miles can be quite another. "Max power" isn't the only parameter to evaluate cams based on.

 

My old cam was mild duration high lift on my AFR 195 headed 383 and it had a very broad powerband. I contribute that to 2 things: Duration spread on the cam and the high lift/short duration lobe.

hydraulic roller: 286/306 230/245 .603/.613 w/ 1.6 rockers. 109 lsa. 3600 stall, so the dyno pull started about there. From 4000-5000 it was about same torque. From 6200-6600, about same hp. I shifted that thing at 6800 sometimes and ET/MPH didnt change much at all if any. Long exhaust duration I think kept power hanging on as rpms rose. that cam sounded cool and made very good power. 3450lb car, 11.4 at 118.x, best trap 119.1 in 2500-ish ft DA in warm summer air. Never ran it in cold air but 11.2's at over 120 were likely.

 

Don`t know if my cam fits the description or not, but it`s a 233 @ .050 .625 lift on a 109 sep.
Relatively short IMO

 

UD Harold cut me a cam for my 502 bbc conversion to a solid roller with this idea in mind, with a quick ramp:

249/255 at 0.050
.702/670
LSA 112

 

here's some more info on the lobes of the crower cam.. Are these aggressive ramps? If so, are they too much for my build?

 

UD Harold set me up with one of his 24 hour grind cams for my 383. Its a solid roller 249/255 640/640 lift. he said it should blow the back tires off my street car..:yes:

 

I do have a old Kaw 1000 with a 1070cc kit and cams that are higher lift than stock but not much more duration. With 10.25:1 it does ping on pump gas. I wish the cams had more duration to lower the cyl pressure at lower rpms so I could run pump gas without adding octane booster. I have tried reducing the timing but even a couple degrees initial really affect performance.

 

I had a Camshaft Innovations solid roller cam in my 489 that had very short intake duration and a decent amount of exhaust duration (239int/267exh). Lift was .721 int/.710exh on a 108ls. This cam worked really well but was a bear on valve springs. This cam powered my 3700lb skylark to a 10.09@131.6 on pump gas.

 

Thats a crazy spread! Good #s though

 

What would be my horsepower estimates and what size stall would be best for mostly street/ some strip on the build.

 

Anyone against using the summitt brand 750 carb on this combo? I've seen some dyno numbers on the mechanical version, but haven't on the vacuum secondary version. Advice welcome!!