What part of your tune up is such a departure from competitive engines that the cam has to be different?
Excellent question. Many feel that they will benefit more from a special grind verses off the shelf stuff. Just not true, especially if you are using off the shelf parts for everything else and building in the 550 or under HP range. On the second part of the OP's question, it is always smart to get a few different cam vendors opinions when you are looking for a custom grind. Fill out their web sight form and send it in.
This IS the problem. If you don't flow the intake system, don't know all the numbers then off the shelf is probably good enough. But no 2 engines are ever exactly alike.
What I can't grasp is why is it a big deal to pay the same (or even a few $$$ more) to get a cam that is spec'd to YOUR cmbination. If you don't think it's a big deal, make up 3 engines, all with slightly different specs i.e. one with a dual plane, one with big headers and one with 1 point more compression. Then call and get cam grinds called out for each one. Something there to learn.
Under that scenario, all engines should have a special cam?? BTW, it ALWAYS cost more for a special grind cam. I, actually am running a special grind cam from Comp due to my combination ( blower motor, big heavy car, etc. ). When I purchased the cam A few years ago, I filled out the cam form from several cam suppliers. At the time, I was running some cast iron heads that flowed in the 260cfm range. About a year ago I up graded to fully ported aluminum heads that the supplier had flow numbers on - 299 cfm at .600 lift. Everything else stayed virtually the same. Sent a new cam form in with the head changes to the same guys I originally sent to. Got one no reply. Comp replied with a "suggest no changes". Other cam response was " we can't supply anything better than what you are using". Point I was trying to make is, in many cases, that "I need a special cam" is over blown and more of a comfort zone thing for more $. Many cam sellers offer in the range of 15 different off the shelf grinds for any particular cam type, flat tappet, hyd, roller, etc. Covers a lot of different engine combinations and they have already done the work on the matching valve train components to keep many of us out of trouble. I can surely ( and don't call me Shirley ) see special grinds when you are making large HP with many very specialized parts. That's not what I am talking about.
