I will never go back to headers and headeraches.

Is the issue leaks or cracks? Are manifolds for reliable?

I ordered some in 2020, cancelled it after over a year. Checked back with him not long ago, hasnt had them in 3 years now. Customer was just planning a dyno session and said he was gonna buy some to try, I said good luck. Claims he was told they had them coming in june but thats NOT definitive whatsoever!

That’s sad. Those were supposed to be good.

I may have bought the last pair to come out of the foundry. June 2019

At your power level , any decent manifold will do just fine. I would go with stainless marine myself as their customer service is excellent. I am running the Gen3 on my setup and am very happy. Imco powerflow is a pretty slick setup but I couldn’t fit it under my hatch. Like others , I initially wanted the Thunder and lightning setup but they seem to be nla. I certainly wouldn’t put a used exhaust on a new engine

I have Lightning headers that came with the boat in 1998. I've sent them in and had them tested and they are still like new. Of course I store my boat in a heated garage and don't leave it in the water overnight unless I'm staying on it. They are a bit loud, but I do have a pretty well built 524. When it starts to hit the power band it really sounds mean.