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factory mk4 block vs aftermarket

sintax

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I'm wanting to start collecting parts for the next engine build, I'd like to do a forced induction setup. Assuming i'm looking at staying around 496ci does it make much sense to move to an aftermarket block or bowtie block? Assuming proper machining, studded mains, and proper assembly, are there any concerns with a factory block holding 1000 hp? I can see the advantages of the aftermarket block if I was going to a displacement in the 540-600 range, but am I missing anything else?

Either way I have to find a block, I have a lead on a +10 over mk4 4 bolt main.
 

obnoxious001

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.010" over? That's super unusual, normal first bore is .030", rarely .020".

If it's .100" over, better make sure it's sound and ready to use at that bore. Don't be afraid to use a tall deck depending on your combination of intake and ignition, since it can yield better rod angle.
 

sintax

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.010" over? That's super unusual, normal first bore is .030", rarely .020".

If it's .100" over, better make sure it's sound and ready to use at that bore. Don't be afraid to use a tall deck depending on your combination of intake and ignition, since it can yield better rod angle.

Sorry Barry, I double checked and it is indeed at 30 over

I'm unsure of my direction at this point on manifold, I'm not having a ton of luck digging up a turbo kit, so I may just end up tossing an 871 or 1071 on there and calling it a day. If I can find a turbo kit in the next year I'll head that way, if not i'll just do the SC.
 

sintax

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Just buy the one that @obnoxious001 has almost ready to go!

haha I’m with you there. That would be the smart thing, but I’m trying to not have the ol lady kill me. I just rebuilt my existing setup, so I’ll have to nickel and dime this one together over the next year or so to keep it under the radar.

I am going to talk to Barry about building it for me though.
 

obnoxious001

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If you got lucky and found a good aftermarket block, it wouldn't be a bad thing.

1000 hp with a 496 is not necessarily a pump gas, walk in the park deal. Turbo may yield more power due to not heating the intake charge as much as a supercharger.

I do have some pieces for a 509 cubic inch forced induction engine that I would sell with a build package. Bowtie block finished at 4.500", new Eagle H beam rods with L19 bolts if I recall, new JE pistons to fit the block with a small dish to make compression blower/turbo friendly.

I am also exploring the new Speedmaster block with billet splayed main caps at a pretty reasonable price, can let you know once I check fit and measurements on one.
 

sintax

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If you got lucky and found a good aftermarket block, it wouldn't be a bad thing.

1000 hp with a 496 is not necessarily a pump gas, walk in the park deal. Turbo may yield more power due to not heating the intake charge as much as a supercharger.

I do have some pieces for a 509 cubic inch forced induction engine that I would sell with a build package. Bowtie block finished at 4.500", new Eagle H beam rods with L19 bolts if I recall, new JE pistons to fit the block with a small dish to make compression blower/turbo friendly.

I am also exploring the new Speedmaster block with billet splayed main caps at a pretty reasonable price, can let you know once I check fit and measurements on one.

totally understandable on the horsepower, that number was more of a buffer number. At the end of the day it’s going into a lake boat, but I like to overbuild a bit.

maybe we could meet up again this spring when I head back out and chat about some build options.
 

obnoxious001

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Other thing is the age of most of the MK IV blocks starts to show itself. Anything run in a boat is liable to have some issues with cylinder head bolt threads in the block.
 
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