Just bought new Parts Place Battery tray and hold down bracket.
At the same time, I bought new battery from Wallmart.

Now the new hold down bracket won't clamp properly on the new battery. When I tighten the clamp, there does not appear to be enough grip to hold the battery.

Anyone had similar experience? Is the repro hold down bracket/clamp not the same as stock or are the new batteries today missing the bottom ridge to engage with the clamp? This is on a1971 Cutlass

 

I recently bought the PP battery tray ( the small one) and hold-down and a Wallyworld battery (MAXX-34S model) too. They all play nicely in my 69 Cutlass. Something silly to check ( don't ask how I know) is to make sure the hold-down is face up. Try flipping it over before screwing it down.

By the way, the repop tray was pretty darn close to the factory model, except it lacked 40years of acid damage.

 

Although you probably already checked, did you get the correct size of battery?
I have been sold the wrong ones before because the store's computers were wrong.

 

x2 what Rob said.