Search the Community

Hi guys, First post on the Malibu crew page. Have been scrolling around the page digging up whatever information I can find on the Callaway 365 hammerhead. We recently purchased a 1998 Malibu response lx with the hammerhead 365 with 1000hrs on it and the hull. so far what I know about the hammerhead is: -The stock 1998 hammerhead is based on the 5.7L -the Hammerhead had GM fast burn aluminum heads and a different cams then the monsoon 5.7. I assume that this is the 40 horsepower difference between the classic 5.7l and the Hammerhead. What I know about our boat: -Boat has a jasper block allegedly installed at 400 hull hours after the original owner did a poor winterization. All jasper could tell me from the sticker on the block was that it was installed pre 2014. -The owner I purchased it from had had it for 9 years -upgraded it to stargazer -It will eventually need a exhaust manifold as there is a small crack right at where the manifold bends. It drips a very small amount of water when running, will run as is and repair at a later date. -kept the interior in absolutely incredible condition for its age. So my questions to any hammerhead owners are what are you seeing for top speeds and RPM? So far we are happy with the boat but I am not really that impressed with the motor. We have three friends each with responses (1 98 and 2 99s) all have the monsoon and they are basically preforming the exact same to slightly better than the hammerhead. With a acme 449 on the boat we saw 47.8 mph at 5050rpm. I know these boats aren't built for speed, they are tow boats but I was expecting slightly better speeds than the monsoon. I have a 515 on the way and that will be the prop I consistently use. The boat appears to have some sort of vibration that I cant quite figure out, the prop is in perfect shape so maybe I am just not use to the cam of the hammerhead? The boat almost feels slower out of the hole than the monsoon as well? maybe having a fuel supply issue? I plan to change the fuel filter soon and it does still have the hard lines from indmar so it does have a fuel hammering if you back off the throttle rapidly. ANY other items I should watch for on this motor? I know oil consumption has been an issue on these motors but so far no signs of that.

Hello all, Ive tried searching and cant find any detailed information on rebuilding a 383 Hammerhead motor. Does anyone have any experience they can share. I plan on replacing oil pan gasket, water pump gaskets, thermostat gaskets, intake gasket, intake plenum gasket, exhaust to cylinder head gasket, drive/flex plate, head gasket, valve cover gaskets, etxcat re-plumb kit. If anyone has anything else I should change please let me know. The information that i cant find is on the internals, Does anyone have information they can share on part numbers or clearances for rod bearings, main bearings, thrust bearings, piston ring replacement. Thanks

Hello! New to the site! I recently bought a 2008 247 LSV with the Hammerhead engine. We have put about 35 hours on it this summer and it has been great, just rolled over 500 hours! Going to do an oil change tomorrow. I can't seem to find anywhere on the site, suggestions about the best way to drain the oil (how to catch it all without it making a mess in the hull). I have Valvoline 50W Conventional to put in and a mercury filter, both to match what the dealer used before I bought it. Any other tips, tricks or need to knows? Oil PSI seems good with that oil at around 40psi at idle and at most around 58-60psi during a hard pull. Seems to maintain pressure and run well! Lastly, I notice what sounds like a belt chirp at idle but only some trips out. As soon as I throttle up around 1500 RPM it disappears. Any suggestions on how to fix this or what it may actually be? Thank you!

Hey Guys i have an 06 23lsv with the hammerhead. 340 hrs on the motor. The engine is hesitating under load and at higher rpm approx 4800 when not under load. It will sometimes pop through the intake if pushed when it starts to hesitate and the check engine message will appear. I have changed fuel filter, plugs, cap and rotor, sensor in the distributor, Coil module, plug wires, and fuel pressure regulator. It throws a crank position sensor code so that has also been changed. There was no wear on the crank sensor. Even with the new sensor it still throws the code as well as the check engine message. Fuel pressure shows 60-70 psi on a gauge and is jumpy. It was the same with the old pressure regulator. Any idea what to look for next? Thanks