Depending on the gasket type & the manifold "fit" to the block & heads, as a general rule, no. I will occasionally use something around water passages. Some guys will use white grease on the manifold side of the gaskets if they plan to do a lot of manifold swaps/changes. My view is that a good fit & correct torque will do more to seal it than goop ever will. Some gaskets like the blue Felpros don't work very well with sealer. My personal preference are the Mr. Gasket Ultra Seal sets (naturally, not available for a Y), though I detest any other Mr. Gasket product ever made.
Ryan, am I correct in assuming that the short block is already assembled by the machine shop? Check the timing chain & gears to verify they are correct, & not set up like most other engines. If you aren't sure what I mean, look at the new t-chain thread in this forum.
Also, take some time to check all the freeze & other plugs to confirm they are in place & correctly installed. It completely sucks to do a two minute/$1.00 procedure once the engine is already in the chassis. On those same lines, make sure the oil pan bolts aren't overtightened. Don't overtorque the valley cover, either.
I'd spend some time making sure it's not bent.
Lash the rockers before you fire it, & check them all over again once the cam is broken in. Hopefully the machine shop used moly cam sauce on it, but I'd go to the local GM parts dept., get a bottle of EOS, paint the rocker shafts, rocker tips, pushrod ends, valve tips, & distributor gear with it, then dump the rest of the bottle over the cam lobes before you seal it up. I'd use 15W-40 Shell Rotella to break it in, or if you want to spend more $$$, Valvoline (or whoever) Racing oil, to get the ZDDP content.
Fill the carb bowl before you start it. There's a saying to the effect of "The ONLY used parts that should ever go back into an engine are a KNOWN GOOD distributor & carburetor", and it makes a good point. Keep a garden hose handy as well to put out fires (hopefully not) & mist the radiator to cool it down. An ABC-rated extinguisher is a good thought too...
Good luck!
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