Thread: cam question

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ok this is for my friend, hes got a 350 with somewhere close to a 11:1 CR with stock heads he got ported with 1.95 1.50 valves
he doesnt know what size cam to go with hes thinking of a cam with
.533/.533 lift
.245/264 duration at .050 inch
.312/.322 advertised duration
or this one,
.570/.570 lift
.274/.274 duration at .050 inch
.320/.320 advertised duration
what do you guys think?

Too much cam for the c.r.
Call a cam grinder for a recommendation.

too much lift or duration

duration

this any better
Duration at 050 inch Lift: 244 int./254 exh.
Advertised Duration: 302 int./312 exh

Personally, I'd be thinkin' something like this....

http://www.cranecams.com/?show=brows...tType=camshaft

or this...

http://www.cranecams.com/?show=brows...tType=camshaft

I hope you have enough cylinder head to make this type of cam work at 7,000+.

ill tell him but i think hes got his heart set on this
244/254 at .050 lift
and .510/.533 lift
thanks

whatever.
You can see that these two cams I've shown have the intake valve closing at 46 to 48 degrees after bottom dead center (measured at 0.050" lift). If you close the intake later than that, you won't trap as much cylinder pressure and the motor will be slower. CHOOSE A CAM WITH LOGIC, NOT EMOTIONS.

Originally posted by muteboy49
ill tell him but i think hes got his heart set on this
244/254 at .050 lift
and .510/.533 lift
thanks

Try hard to convince him to listen. Tech knows his stuff. You must use a cam the engine wants, not what the person wants. Race car performance doesn't come by taking a shortcut straight to racecar cam. The entire engine must be taken into account for it's purpose. Just about any head that uses 1.94 valves is most certainly too small for those cams. Even cars that have the racecar "LOPE" have a fake, hollow sound that an experienced hotrodder can immediately notice if the compression isn't matched to the cam.

The biggest mistakes novices make are choosing a cam that is way too big and a carburetor that is way too big. It is much better to have a cam and a carb a little on the small side than to have one too big. It is no fun fighting an ill-performing engine that does not live up to expectations because of mismatched parts. It is also a waste of a lot of money. You have to think of an engine as the sum of its parts, not just one part. Every choice you make will affect every other choice you make. Do your research and take the advice of experienced people and you won't go wrong.

i told him to go with something like mine (smaller lift and duration) and told him hes gonna be sad when he gets the motor done and he said he might change his mind. i really dont care
thanks guys!

Some people just have to learn the hard way.

yep. and im not helping him pull his motor again lol

muteboy, the thing is, whatever cam he uses, the motor will sound o.k. and he'll brag about his choice. What he doesn't realize is that with a shorter cam, all the components would be matched up and he'd make more power. He'll never know that though, because he'll never dyno the combinations to find out.

In order to help you a little more, please read this paper I compiled about camshafts. It starts off with an excellent piece written by Dimitri Elgin, owner of Elgin Cams......
http://streetmachinesoftablerock.com...topic.php?t=78

thank you very much
i will read it but i wont tell my buddy because i want to see the look on his face when i beat him at the track