Marine vs. land 502?

[05crewcab]

Saw this ad on Craigs tonight, and am wondering what the differences are between marine spec GM motors and Vehicle spec motors?

http://minneapolis.craigslist.org/hn...939270930.html

...and, could a person use all those components in the ad on a bored out 454 block in their truck?

[dwcsr]

The only difference in the base motor that you may find is that the rotaion is counter clockwise or clockwise. If its a two screw boat then it had one of each

[05crewcab]

so what determines the counter rotation? is it dictated by the cam and distributor?

[cdowns]

that is alot of money for a parts motor// i see l 454 complete motors for less that are ready to drop in and run
tes cam is different on counter rotation,even if its regular rotation cam isnt good or the street

block is trash but everything else is good?? i'd b skeptical

[QKENUF4U]

from what ive found reading on the net and dealing w/ my bosses 578 stroker boat motor...

boat blocks come straight off the same assembly line as car blocks. the blocks are then sent to whoever bought them and they are prepared there for boat use

they do use a BOAT only cam (different lift/duration since boats spend their lives under a load)

they use different head gaskets to withstand water (salt)

they may line the inside of the water jackets to keep corrision at bay

not all boats run reverse rotation water pumps

it will def. be HD gm parts inside (steel crank, 7/16 rods, etc.) so it might be worth the money if you already have a good block....

[gkesseru]

Since marine engines spend their life at near full loads, they are usually a 4 bolt as the one in the ad.
If the engine in the ad has a cracked block, it is probably because of ice. Heads therefore are also suspect and may have cracks that are yet to show.

[dwcsr]

Cam determines the rotaions, you also need a reverse starter, water pump.
The firing orders would be
Std. Rotation 1-8-4-3-6-5-7-2
Reverse Rotation 1-2-7-5-6-3-4-8
In a 2 screw boat and the screws turned the same way then the boat would always want to pull to port (right) or starboard (left)

[rollinhard]

The problem with this motor is its a gen V i guess thats not a problem unless your building a gen V or gen VI they have one peice rear seals so the crank is useless in blocks before 1993 the pistons are 4.470 bore wich is 220thou over bore on a 454, the heads appear to be the non adjustable valve train and will probably only fit the later block as the water core holes wont line up. like said it would be good if buildin a later 454 ho or 502 again but is useless really on the older stuff. The rods are good but 800 dollars and all you will use is a set of chevy dot rods isnt worth it.
My 2 cents

[leddzepp]

Originally Posted by dwcsr

port (right) or starboard (left)

I think you have these reversed...

[dwcsr]

Originally Posted by leddzepp

I think you have these reversed...

I did it should be port left, starboard right,

[oldblue1968chevy]

port-left
starboard-right

LOL

[ulakovic22]

I would keep looking. Nothing wrong with boat motors, I have one, but you need to make sure they aren't corroded too bad. Crank, rods, pistons, heads, etc. are all the same as a automobile.

Edit: The other guy is right though about the Gen V block. It doesn't have a provision for a mechanical fuel pump, so you would have to go electric. The only other option would be a Gen 6, you can't bore out a Gen 4 to accomodate a 502 piston.