If I were to set up my rockers/springs retainers pushrods and all that to the stock cam and then swap cams will I need to redo anything?

 

only if its on a small base circle

 

which big name ones are?

 

usually they are only on a small circle if they are ground for a stroker

 

So generic lt1 cams should be ok then.... excellent...

 

Zeet isn't exactly correct. Your valvetrain geometry will need to be checked again. I'd leave it alone until I had the new cam in.

 

I'd really like to know how a change in lobe profile alone affects the geometric relationship between the camshaft and the rocker arm. This assumes NOTHING else has changed.

 

A change in cam profile will sometimes require a longer (or shorter) pushrod to regain the proper valve tip geometry.

There is a limited amount of space for cam lobes. More lift usually means a smaller base circle, which in turn changes the position of the lifter downward. if you use the same pushrod, the fulcrum has now also lowered a corresponding amount, and your rocker arm geometry will now be 'off'.

You cannot *assume* that because your geometry was correct with the stock cam that it will be correct with *any* other cam. This line of thinking leads to wasted money and problems that sometimes include blown motors.

 

Most cams are ground so that the max lift point on the cam is just slightly under the diameter of the cam journal...so with different lift amounts will come different base circle diameter....unless the cam is ordered specifically with a small base circle for crankshaft clearance on strokers...or the cam grinder screws up like LPE/Comp did on mine ...but you do get a billet cam core on small base circles which is good after seeing my previous Comp cam starting to wear excessively on the lobes after only 15k miles or so..the outter surface had already been worn through.

 

Ya need to check it.
Most of the time with extra lift ya need pushrods.