273/ 2 barrel camshaft options

coast2coastkidd85 said
Hello and thank you for the response. I appreciate the knowledge and sorry to hear about your experience. That’s exactly why I am here, I don’t know what I don’t know, it seems that any aftermarket cam may greatly affect or upset the cam related components I’m working with. Until I hear from the machine shop I’m hopeful for a refrains and resurface with what I have, if not I’m reading more on weather the isky option would “over cam” the existing setup. Thanks again for sharing!

The Isky cam above is not over "over cam" for your engine with a 216 @ 0.050" duration. The definition of "over cammed" that I use is when someone put in a cam without thinking about the rest of the engine. The cam is the first thing you pick and that choice defines the personality and usage of the engine. _Everything_ after this is an output that is calculated based on the cam selected. The thing that I have seen most people get wrong is thinking a cam swap will give them instant magical awesome engine. When you make that cam selection you _must_ have the correct compression for that cam or will kill low end torque. The cam may offer a more high end breathing but because that longer duration cam has more overlap the cranking and dynamic compression goes down. The main factors in low RPM (I mean RPM that you use when drive normally on the street) are cylinder pressure and cubic inches. Bigger cam without increasing your compression will make low end torque worse and sometimes way worse, i.e. over cammed. This is really true on 225 slants (typically 7.5:1 from the factory) and later 318's (typically only a little better). Have your machine shop calculate/measure what the compression ratio will be when they are done then decide what cam to use. I personally would get one ground at Oregon Cams that matches well with your engine (most commercial cams will have to much LCA for stock heads). The heads don't flow well and have small valves so the other thing (based on David Vizards methods) is you want a low LCA (like 108 and with that engine maybe 106) like that ISKY cam is, though you need to be careful if you have too much duration that will give you more overlap and the same things start to occur. Need to know 3 things before you can really get a good cam recommendation

1) What are you trying to improve, low end torque/power or make the engine run better at high RPMs
2) What is your static compression and depending on the first answer this may need to change.
3) Are you doing anything to the heads to make the flow better.

Jim