5.0 to 5.3

My old 305 5.0 vortec it done. Found a very good deal on used 5.3. Will anything off of 5.0 fit 5.3? 5.3 is just long block will need all external parts. and exhaust plus not even sure it will bolt up. Any advice so I dont make a huge mistake buying 5.4 would be great. Thanks

Re: 5.0 to 5.3

The 5.3 (5.4?) has never been used by mercruiser or anyone else. Not sure what all changes, but I would bet it's not going to accept all the marine parts from a 5.0.

Re: 5.0 to 5.3

If I was replacing my 5.0 or 5.7 I would just buy a new long block. Here is a link to Ebay for Vortec 5.7. Not sure it would fit but don't see why not.

http://cgi.ebay.com/ebaymotors/1253...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

There will be no warranty for marine use.

I would venture to say the head gaskets are the same as marine until someone can prove otherwise with facts for these new motors. That may take a call to the factory in Mexico, I assume. Why would GM use different parts as a big part of the sales are for marine now? They may have some kind of deal with the marine industry. These already have the brass plugs also I believe. Can't beat it except if you rebuild it yourself, maybe.

If you have closed cooling you don't need to change anything except the oil pan. If you don't have closed cooling, which I highly recommend, you may want a marine version with marine head gaskets, marine cam, I guess. I think they can be found for around $2300-$2500 plus shipping. Rebuilt would be another option but much more risky.

I don't think a 5.3 will work or they would have started offering those instead of the 5.7 as it is an improved block, etc. What I want is an all aluminum motor and exhaust and fuel injection. Take the mercruiser out of the dark ages. Works good just heavy.