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i found a 427 tall deck with these numbers 473478 and just to the left, it has marine casted in it. it came from a heavy duty service truck with 85k on the odometer. hasnt ran for a while, but was running before the truck sat. id like to know what the complete engine is worth meaning what are most 427 tall deck blocks going for these days. also, did they all have marine casted in them or just a select few? i came up with nothing. thanks for any info.
 

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Some guy
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The only thing of real value in that engine is the block. Mortec shows it: 473478.....427T......77-90...4-bolt

The heads will almost certainly be small port heads, should have a 1053 steel crank, 4 ring heavy truck pistons. The "truck" rods are a little beefier and heavier than regular 3/8" GM rods, but now days most people go aftermarket.

I don't know for sure on the "marine" part. There were some later year "marine" castings that had heavier walls and could be bored out further, but not sure which casting numbers those are besides the "bowtie" ones.
 

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Some guy
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cool, thanks for the reply. any idea what the block is worth if in good condition?
I happen to like using tall decks, but not everyone does. I would put the value about the same as a standard deck 4 bolt 454 block, perhaps around $400 in Southern California still.
 

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The blocks that have "marine" casted into them means that it is a high nickel content in the iron and was done for corrosion reasons:)bulb
 

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jetboataholic
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Like this? See pics below. The second picture is of the "marine" tag.

Is it just the block or is it a long block or a short block? I think I paid like $1200 for my long block, it was bored 0.060" over, flat top pistons, and mine came with large oval port heads, but basically a stock engine. These blocks are beefy and I'm told that they can take a fairly large overbore.
 

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"The" masheenist
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The blocks that have "marine" casted into them means that it is a high nickel content in the iron and was done for corrosion reasons:)bulb
....and hard as fuck to machine.
 

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Look at the bottom of the cylinder bores, most 427 tall decks don't have the clearance notches to allow installation of a 454 crank, although not a whole lot of metal needs to be removed. Before the installation of a 496 crank we fill the bottom of the water jackets with about 1 1/2" of hard block filler before we grind clearance notches in case we strike water. We have seen several 427/496 engines where they initially didn't have water problems, but rusted through the new clearance notches within 2 years and filled the crankcase with water. In our experience, 1 out of 3 427 truck blocks are cracked somewhere. We won't buy any 427 truck blocks unless we bake, blast, and mag them first. I prefer tall deck blocks and long rods. TIMINATOR
 
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