My 94 battery (for a350/300HP) needs replacement. The owner's manual calls for a 75B-72.

If you drive the car regularly, the stock battery is fine. Using a higher cranking amp battery will not hurt anything at all, so...it's really your choice. Unless you have added more electrical stuff like a stereo system, alarm, etc., I would stay with what came in it, myself.

Not sure where you are but if you're in the south, you don't even need the cold cranking amps that GM required to pass cold weather tests. I keep a "Battery Tender" on mine all the time. The parasitic loads are a lot greater than the old days. I wondered what relay I could hear clicking when the battery was connected. I'm pretty sure it's the series fan relay. It pulls in as soon as you connect a battery and stays that way until high speed is signalled from the ECU and it drops it out to put the fans in parallel.

I have an 87 and, when my battery went bad, I put in a red-top Optima.  It's been great.  Has more CCAs, is gel-filled, so it lasts longer, is better in heat and cold, and, as a big plus, it's a smaller size, so I could get it in without unhooking all the struts and brackets or side panels that I had to get out of the way when I put in a standard, bigger battery the first time.  The Optima slipped in easier and has lasted almost 3 years in the Arizona heat, so far.  If you drive it a lot, that's something to consider.  If you only drive it to shows, then you may want the look of a standard battery.  Either way, it's OK.

It is the heat that destroys or shortens the life of a battery in general.
A larger capacity battery will have no detrimental effects on any vehicle. Electrically speaking, the battery does NOT push current out to the surrounding circuitry... it is a source and allows the devices in the circuits connected to draw from it. If anything an extra capacity battery will be an extraneous expense since you will be paying for something that you may never utilize.

Rich

BTW - I have a standard battery from Sam's Club. And every time it fails I just bring it in and all I am charged is a (I call) a nusance fee of $1.50-$2.50 for a replacement completely new battery. I am in south Florida and have replaced the battery 2 times in the 4 years I have had my 'vette. I have NOT paid full price for a new battery yet.