ok well i have already posted this question with others but no one answered this question. i have a 87 IROC, for now it is stock but here are the plans

slp runners
polished plenium
vortec heads
slp headers
high flow cat
cat back system (not sure which yet)
3.73 gears
fuel presure regulator
roller rockers

now the engine runs great

i dont know much about cams and i was leaning towards the zz4 cam but i wasnt sure if that was a good cam for my car or something, anyway, if anyone could let me know what would be a good cam to put into my 305 with those upgrades.

thanks a bunch

 

For a 305 (especially being monitored by an ECM).... you want to avoid too much duration, and concentrate on lift. If you want the 305 to run at it's full potential, then you're going to have to go with a roller camshaft (the 305 needs all the help it can get to achieve HP)....

Check out the Crane Powermax Cams, and find one with just enough duration (don't worry about lift yet.... as this can always be made up by using a 'higher' in ratio rocker arm).

I can't really recommend one without knowing the work done to the Vortec heads.... and if you decide to go with the stockers, then you'll definitely need stronger valve springs.

 

what is too much of a duration on a cam, whats the duration and lift mean in the cam, i do realize that its how long the and how much the valves open but i dont know whats too big or too much, if you could give me a little insight on it to give me an idea

thanks

 

That's right....

Duration is how long the valve stays open (opens earlier, closes late).

Lift is how far the valve is opened (which increases airflow).

Too much duration will give the motor a 'rumpity' sound (wanting to 'almost' stall in a way), and will more than likely affect the ECM's signals (unless you get a custom chip to adapt to it of course).

Lift can be achieved two ways... either by getting a longer lobed cam, or a longer ratio rocker arm. Do the latter, as it's much easier to change rocker's, than it is to change cams...

(Of course, more lift requires a stronger valve spring.... as the stock ones can't handle the added strain).

It all depends on what you're after, and at what RPM range you want it to peak at....