my question is how can you tell when a cam is to big (not lift) but duration. i understand the lift on the cam and how it should coinside with the flow of the head, but im not clear on the duration factor of the cam. i mean how do you know if the cam is to big far as duration.

let say i know how high i can with the lift on the cam with out getting turbulence. but should i get a cam like the hot cam or a 252 258 with a 530 lift (just an example) but you know what i mean. just what are the determining factors far as duration goes. i know the more duration the more topend and loss of bottom end and drivability. just looking for a reason not to go with a huge cam. im not looking for a "well it gets bad gas mileage" kinda of answer im looking for technical answer.
sorry if im not clear.

 

I'm not sure this will help you pick a cam, but it may help you understand why you might pick a certain sized cam. Its an article I wrote a couple of months ago for my club's newsletter:

http://mtfba.org/chris/techarticles/camtalk.htm

 

That was an OUTSTANDING article. Very informative. Awesome read for anyone fuzzy on cams. Thanks!