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Renegade jet
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472 Posts
Discussion Starter #1
I found a nice 502 gen 5 for sale for $4500, what are the differences in this block from a gen 4 bbc. Will oil pan, intake manifold, etc. interchange? It has a set of gen 4 781 heads on it, will these work on this motor? or should I run away. Thanks for the help.
 

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Boat Nut
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5,131 Posts
oil pan, timing cover, and crankshaft are different. everything else is bolt on.
 

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3,739 Posts
gen v is kind of the red headed step child of the bunch. I'd keep looking. there is a nice 454 gen vi in the spam section intake, headers, oil pan, ignition and berk pump for $3500.

the gen 5 blocks are special in the case that the water holes don't match up with other mark iv and gen vi heads. Special gaskets are required to ensure water leakage does not occur.
 

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4,549 Posts
i ran protopline aftermarket heads on my gen 5 with the right head gaskets, boats still running strong 5 seasons later without issue last i heard. it can be done, but like others said, look around.
 

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Renegade jet
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472 Posts
Discussion Starter #7
There are some nice engines in the spam section, but they are all on the left coast. :mad: This one is close to my house, but I don't want to buy a bunch of new stuff to make it work.
 

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388 Posts
Most aftermarket heads and some Mark IV heads have enough material to seal and will fit. As to which ones I can't say, I've been told each installation needs to be checked for proper sealing. Most head gaskets now should fit all blocks and heads mentioned above in regards to sealing. Also Gen v and Gen vi heads are essentially the same, so gen vi heads are a direct bolt on. The gen vi block was revise to not have this issue along with a few other revisions.

I don't know if this has been mentioned yet but the gen v production block doesn't allow for a mechanical fuel. And they're all 4 bolt mains.
 

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Premium Member
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257 Posts
gen 6 the way to go

just so happens I have one carb to pan msd 850 dp 10 qt dooley came out of my placecraft and was gonna save it for a cruizer but bought a pontoon so no need 4 it iron head motor very low time built by boostpower marine in 99. simple drop it in let her rip aprox 490 horse 540 tq je pistons 8.875 cr very low key pump gas deal lookin for 5k obo pm if interested john
 

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1,185 Posts
i ran protopline aftermarket heads on my gen 5 with the right head gaskets, boats still running strong 5 seasons later without issue last i heard. it can be done, but like others said, look around.

Good to know for my Gen V.
thnx!!
 
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