I see various posts with pictures of red top Optima batteries.
I did some measurements but I think you would have to modify the drain pan if you installed one on a stock 73 914 2.0L in the normal spot for the battery.

We are talking all stock stuff here as far as the engine.

Anyone have any experince here? Will one fit?
Thanks

Can't help you with the rain tray since i never had one, but the Optima batteries have lost a lot of their reliability over the last 10 years. They have had a lot of quality issues lately.

I'm looking to move on to something better ...

If you get a dry cell battery like the red top, make sure you have the correct charger and never let it completely discharge or it will be ruined.

I changed over to a Red Top last year in my stock (except for carbs) '74 with a rain tray. No issues with fit.

.......They supposedly don't leak? thats all I know?
I noticed battery reliability changes with the builder
(who gets the contract)

See if the exide orbital battery will fit. Optimas are one of the worst batteries made now. So bad my brother quit installing them at his customs shop because he was loosing too much money having to warranty them. 2 year battery tops now.

fit is fine with rain tray. hard to maintain properly it seems though, or quality is lacking - take your pick.

I just installed one a couple months ago, the only thing you need to do for it to fit in the stock location is to grind/cut off the tabs at each end of the battery so it will fit in the battery tray and use their battery clamp.

I have an Optima 75/25 installed, no mods needed outside of using an Optima battery mount.

Must say I like the side posts, makes for easier/cleaner battery wiring. But must also say I'm not thrilled with Optimas. I just replaced a 10 month old one (warranty replacement). As for chargers, everyone says not to use a standard charger, but Optima's directions say otherwise. I just installed a battery tender yesterday in hopes of keeping it better charged/conditioned over the winter, so we'll see how long this one lasts...

What exact model did you install?
Red Blue??

The only batteries I've seen with worse reliability than the Optimas have been the braille racing batteries.

I tried to convince myself that I just got a bad one or two batteries from Optima, but my fourth one in like 4 years failed about 6 months ago. None of them older than 3 years. Never again.

Got a pile of dead optimas in the shop next to the pile of dead braille batteries.

Try odyssey battery

Red