duration dictates how long the valves remain open. Longer they are open the more air they can take in. At higher rpms you need more duration and overlap to allow air to come in and exhaust to exit, since the higher the rpm, the faster the piston is moving in the cylinder and the valves are opening and closing quicker.

So add abit of duration and overlap and you should beable to allow more air flow thru the motor at abit higher rpm and thus make more power. Provided you have a set of heads that will flow the air needed as well as the intake flow/runner length required.

That works against it on the low end since the vales are open so long at low piston speeds, it bleeds off cylinder pressure and thus less power is made. thats the trade off, high rpm power or low rpm power. Its all about cylinder pressure and where (rpm wise) you build the most


with a cam you need a higher stall converter for auto trans to keep the rpms up on the motor. With the right tune and converter/gear combo, you can make a large cammed motor move around well at low rpms. Still wont be as good as a smaller cam tho since your losing that cylinder pressure. thats why you need compression to keep pressure up with those big cams to help build that low rpm power.

 

Well mine is still a 350 with stock bore. Its not a 355 just to clear that up.

The cam has a 112 LSA also. As far as my opinion, I love the cam. I have even knocked around the idea of going to 1.6 rr's. The difference is that my AFR's will flow great up to .550 lift. The Edelbrock RPM airgap I have is port matched and flowed with the heads.

If you go with the 282, get it ground on a 112 LSA. We thought that my motor was 10.3 to 1 compression, but We redid the numbers and I think it is a little higher.

Just make your Heads/cam/intake RPM range match and it should be a strong runner.

 

I never understood why AFR makes a 180 head but always compares the 195????

 

The 195 is their PRIDE AND JOY. they always proclaim its the best head for any street/strip motor from 350 to over 406+ inches, and they have a point. smaller runner volume yet great flow yeilds great velocity of the air charge. You cant go wrong with the 195 on a 350 or so, but for some mild setups that 180 may make more torque.

The 180 would be the hot ticket for cubes less than 350 thats for sure. Like if you build a destroked 350 block to a 302, or have a 327. OR even throw that head on a 305. Its been done before.

 

Thanks for everyone's input. Well, my intake is matched to my heads already, and i think i am willing to give up 10 peak hp for more lower peak power and better streetability. if the gain over the bigger cam was more drastic then i would go with it but it doesnt seem to be.

 

yeah i dont think its gonna make a whole lot more power than the 276 cam. maybe 10-15, thats tops on those heads

 

so not to bring anything back from the dead like newbs tend to do but this seemed like a pretty heated conversation on the differences between the cams. So my question is how did it work out in the end? IROC, are you happy with your 276 with the 110 LSA?

 

whice one of these cams would work best with a 406 with a (SuperRam making peak power at 5500) and Brodix 200IK heads