im building my friends 331 for him and im wanting to know about putting on the crank sprocket because there is 3 different positions. which position should i put it at? thanks for the help
Cylinder #1 must be at TDC.
In most cases the cam sprocket will have only a dot and the crank sprocket will have a key way with a zero, triangle and a square. Better units will have multiple slots with degrees in advance and retard.
I assume you're not going to degree the cam (which is the best method), you'll want to install the cam at zero (0).
I say this because you will not know where the lobe positions are in relation to stroke positions.
Build it up and before starting the engine, crank it a few times without ignition and check cylinder psi. If the psi is within tolerances of the manufactures specs of the camshaft, you should be good to go. If you're psi is too low or too high, you should consider re assigning the camshaft per the camshaft manufacturers suggestion.