I bought a 1989 28 saber less power. It came with bravo drives and transom assemblies plus a few extra parts, including like new Y-pipes for a stock 454 365hp mercruiser motor that was originally installed when new. My question is can I run the stock Y-pipes on the new power, a mercury racing 500HP motor rebuilt to a 509ci? I would love to be able to run the Y-pipes around the docks and maybe pulling kids on the tube. I am going to have to buy exhaust manifolds, probably the stainless marine manifolds that are compatible with switchable exhaust. My main concern is reversion or anything else that could create motor problems.

Yes, but not sure about when pulling a tube.

The carbureted HP 500 (not to be confused with the 500 EFI) is known to have some issues with reversion. Some run into issues, some don't. Not sure I'd try it but it you're aware and bump up the idle, it may help. Watch plugs and oil and signs of issues.

Very good point Tom. Not sure what cams currently used but still something to be aware of. I’d like to see a pic of the boat. The 28’s are a fun boat and miss my old bloody red saber.

Here's a few, and an old one from a previous owner long long time ago, hasn't changed tho.

I believe the motors will have the original 500hp cams. So I guess around the dock probably OK? Would it help to switch to thru hull and rev the motors just before I shut it down?

I remember that boat back when it was new in 89 + - in and around grand haven. Even been for a few rides in it back then. Original owner was friends of who I bought mine from. Nice looking boat. I have a little more detail but not relevant. Anyway congrats.

For sure on the switching. Keep a close eye on things tom mentioned.

I use turn downs

My 99 HP500 has the y pipe and Corsa diverters, but in 99 Mercury put taller risers on the Gil exhaust. I know Hardin sales the taller risers as well for the Gil replacements and I believe Stainless marine has something similar as well. I use my diverters occasionally when going in late or early to the ramp at the Marina it also helps I have large Corsa Mufflers from the factory as well. I try to bump the idle up a little too when using the diverters to the y pipe. As far as pulling the kids on the tube with it closed I would not as it would be too restrictive.

These are the style tails I have and I run the turbulators which probably helps if there is a little reversion.

https://www.cpperformance.com/p-1340...-polished.aspx

Yup. Merc came out later on with taller risers for the hp500’s with reversion issues. Here’s another view