The nice thing about Crane numbers is they tell you all that. Its a single pattern 270@050 .375 lobe lift, 108 LSA. If it were a dual pattern, there would be a 2, 2S,2S1 ect after the lift number. Multiply the lobe lift by your rocker ratio for gross valve lift. And thats a pretty big cam. Very hard core street/strip or race only, depending on your viewpoint.
Well, at some point Chase Knight will find this, he usually does, and he can confirm that for you, but that is the gross lobe lift in the grind number.
I got a note off to crane asking for the old description lets see what they can come up with. maybe they will send me the info from the old catalog, they still have some of that old stuff around. Oh that is just an everyday cam shaft for a fella that owns a street strip car. I would run it if I had it and I don't own a dedicated race car.
Assuming it's a SBC, That's a flat tappet "Competition" cam - similar grinds are going to say "Good upper RPM torque and HP, Rough Idle, RPM range 4400-7600, 11.5-12.5 compression", something along those lines
http://www.enginebuildermag.com/2015/07/camshaft-selection-and-design/ Here is a link to a site that I found recently, did not read this completely but sounds like they take the 'middle ground" approach to street engine building. Pay attention to the sentences highlighted in red. One of the most common mistakes engine builders make when choosing a cam, says one cam supplier, is jumping to the bottom of the catalog page and picking the cam with the biggest numbers. Or, picking a hot cam that has the potential to deliver really big numbers without actually thinking through whether or not this is what a particular application really needs. Everybody wants the hottest cam that will produce the highest peak horsepower numbers, but torque is actually much more important than peak horsepower – especially if you’re building a street performance motor. Torque is what accelerates and pushes a car down the road, not peak horsepower. And the flatter and broader the torque curve, the better the drivability and throttle response you’ll get from the engine.
Thanks guys. I have emailed Crane about another cam I have-no response. I have concerns about the .375 X 1.5 rocker arm ratio giving .563 lift!
What engine is this for? The .563" is gross valve lift, subtract the lash for the net lift figure. What's the intended application? Regards, Chase
HP is not measurable it is calculated from torque and is based on torque and rev potential. Most people have no idea how to pic a cam and that's a fact. I choose by what I know works, now if you don't already know what works then @falcongeorge is your man, he is mister equation and has a ton of them just for cam choice and cam description. My personal preference is an engine that will rev, but unless you are willing to keep 'em reved up or if you are running an automatic they do not make good street engines. Automatics have a tendency to want a pretty loose converter when they are bolted to an revver, not always. You can build an engine that will rev and still have a good broad power band, but it take a complete build to do that not just a cam change. OK now I have made myself feel important let me see if crane wrote me back, they usually suggest that a return will be 24-48 hours. Sometimes the description on those old cams was not really spiffy, for example I have an Engle cam here, 280+ duration .5 lift and the description in the old book was "long duration racing cam." If you are zero decked even with "stock valve reliefs" anything over .5 lift you will need to clay it before final assembly. In a perfect world the intake is chasing the piston down the hole and the piston is chasing the exhaust up but I still like sufficient clearance.
What heads, compression ratio, intake system, rocker ratio, transmission, rear gear, tire size, RPM range, idle quality, vehicle weight, vehicle usage? All info helps.... Regards, Chase
Still looking for an old Crane cam book for specifications on this cam. This is the only comments I need.
24 River view-sorry to be a pain in the A -but being old , I can't read the chart even with a magnifier. Any chance of enlarging the SBC section-also have another camI need info on.Thanks so much
No problem, like slowmotion said just left click it, then click the open in new window icon, then left click it again should be big enough to read then. If that's not working for you send me your email in a "conversation" and I'll send them full size. SBC page added, let me know if you need anything else.
Thanks guys -just what I asked for . Used the button on the upper right"open in new window" got it printed all set.I will probably find my old catalog today!
Yes, this is from the early 1970's. Recommended valve lash is .016" intake, .018" exhaust, at operating temperature. Advertised duration is 332 degrees at .012" cam lift on both intake and exhaust. Duration at .050" cam lift is 270 degrees. Lobe separation is 108 degrees. Cam timing at .050" is: intake opens 32 BTDC, intake closes 58 ABDC, exhaust opens 68 BBDC, exhaust closes 22 ATDC. Basic RPM range is 4200-7200 RPM. This was intended for use in heavy (11 to 13 pounds per cubic inch) drag race applications, high compression, ported heads, etc. Regards, Chase
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