I installed the Mercruiser system. It fits and performs pefectly.

The motor I was asking about was the HP500. Was the one you used for the 454? Thanks.

Yes, I put it on a 454. I have never checked it out, but does Merc. make a kit for a HP500??

Checkmate, That was my question. I think you have to go with another vendor.

I installed a fresh water system on my hp 500. I purchased it from lighthouse marine supply in New York. It was for the engine and manifolds but I quickly found out that the gill manifolds would boil the antifreeze out before the t-stat would open. This was a costly mistake, I busted a manifold. I then only cooled the engine and it works great. The system was for a 454 but it was large enough for a hp500. I am not sure if they still make this system though.