replacing engine blocks.

stunta666 · Newbie Joined: 01 Aug 2006 Posts: 31

Does anyone know if you can use a regular car block as a replacement for the factory marine block? the engine is the mercruiser 305, 5 liter.

redhededstepchild · Criminal Joined: 15 May 2003 Posts: 52 City: Austin

You "can" but it's not recommended. The marine blocks are corrosion protected as well as having non-corrosive freeze plugs and a few other small differences like that, but the main thing is marine engines are built to handle the resistance that the water puts on the hull & prop. Opposed to pushing rolling tires across concrete. Also, you don't (normally) run a car at wide open throttle for an extended period of time like a boat. I've been doing a lot of research on this this week...I just found out that my block cracked as a result of not winterizing Embarassed

boarditup · Addict Joined: 01 Dec 2003 Posts: 731 City: Allendale, MI

The block is the same. The freeze plugs are different. Jasper and several other rebuilding companies offer marinized blocks. The key components are electrical and fuel system. A marine cam and a roller valve train with stiffer spring complete the engine. If you are going to keep your heads, have a valve grind performed so they don't blow by.

Good luck. I had to do this about 5 years ago.