Went to NAPA today to buy a battery, nearing start-up on my 1928 M2. The guy asked me if I wanted an 8-volt instead of 6-volt. He said it would work fine and make things brighter. I didn't buy it but wondering if anyone has any feedback or experience with this.

Hi Greg........

We used to use the 8 volt batteries on the old farm tractors. Made them quicker starting and spun them over a little faster.

If your wiring and ground connections are good the 6 volt battery will work fine

Frank

I know people who use the 8 volt batteries in their cars, and I understand they are a little harder on bulbs due to the extra voltage. However, if as Frank says, the wiring, ground points etc are good, a six volt battery is just fine.

Gord.

When I was a kid, I remember my Dad had an old truck that was hard to start and the starter was weak. He couldn't afford to spend the money to repair the truck properly and an 8 volt battery was cheaper.
The truck started a bit quicker after the replacement but it hastened the demise of the old starter. He had to buy a rebuilt starter and get a proper 6 volt battery anyways!!
That was about the time I learned the proper use and context of profanity,,,,,,

Those 8 volt batteries were a "get by" at best and just prolonged the needed repairs.
Don Shilling

No need for an 8-volt battery. Just good clean and tight connections and the large cables to the starter. Don't use cables for 12-volt systems. Also if car properly timed and carburator adjusted properly, you will have no starting problems.

Bob