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304 VN AERO REBUILD (304 stroked to 350ci flat top pistons std 4" bore)

bjf66

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holden flat top pistons Hyper or forged high compression with or without rods to suit standard 3.025" stroke crank
 
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gtrboyy

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Had a quick look around...

$558 cast scat stroker crank to suit vn rods

https://outlawspeed.com.au/shop/sc930834805627


Forgies like nice srp's $800-$1200
Casties like hypatec $350-$500

Piston same price whether it's a304 or 355...availability/pricing may be pain in butt the way thanks to lockdown bs
 

bjf66

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thanks for that
at this stage im still think of staying with 304,
would like to get the compression up without decking block, so looking for flat top piston, with higher CH than 1.71" to get the compression up
if changed the rod length it would open up more choices, however then may as well throw at 3.48-3.75" stroke crank into her
 

gtrboyy

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To do longer rods may as well go further as need machining etc etc etc...

Cheap hypatecs or whatever flat top casties

Cometic head gasket with a piece out to make it thinner or thinnest headgasket available although cometc is usual trick by av8 peeps...maybe skim 20thou off heads as long as manifold won't need machining.

That way compression is better than whatever it was & leaves room to go further down track if game enough.
 

Immortality

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You can get .040" and .027" Cometic gaskets, the .027" gaskets are more expensive so I would get the .040" gaskets and pull one of the middle layers.

Or skim the crap out of the heads, I'm going this route with a 2nd set I bought cheap.

It's a shame there isn't a simple flat top piston option to suit the 304.

edit: actually there is,

No idea on how good they are though.
 

gtrboyy

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Take too much off heads then need manifold machined or elongating bolt holes.

Then can't use heads again with flat tops unless build it for E85....not so bad I guess.Do ittttt!!!!!
 

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Flat top pistons, thinner gasket and VT heads 10/15 thou off if you dont want to deck the block will raise your CR for a stock banana 304 without going crazy as that will create other issues with parts used.
 

bjf66

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need to keep the VN 0019 heads as goes with engine in Aero, so stuck with the 63cc heads
yes can use 0.027" gaskets
suppose if you used 308 crank which is 3.0625" stoke crank which gets you 0.0375" (close to 0.040") up on the deck height so now the flat top is a flat top without decking the block
However that wouldn't be a 304ci that would be a 308,
however good trick if using 308 block, crank, rods and 304 piston would achieve same result without decking block

Bore: (diameter) 4.0 in. 4.0"
Stroke:3.0625 in. 3.025"
Cylinder Head Volume:63 cc 63 cc
Effective Dome Volume:
Use (-) for Dome and (+) for Dish.
0 cc 0 cc
Deck Clearance:0 in 0 in
Compressed Gasket Thickness:0.027 in 0.043" 0.027"
Number of Cylinders:8 8
CALCULATE​
Compression Ratio :10.21 : 1 9.79 : 1 9.12 : 1
Total Displacement (in.3) :307.88 307.88 304
Total Displacement cc's :5047.21
 

bjf66

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You can get .040" and .027" Cometic gaskets, the .027" gaskets are more expensive so I would get the .040" gaskets and pull one of the middle layers.

Or skim the crap out of the heads, I'm going this route with a 2nd set I bought cheap.

It's a shame there isn't a simple flat top piston option to suit the 304.

edit: actually there is,

No idea on how good they are though.


I sent mace an message on friday and asking for the actual compression ratio and if there are any other options
 

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I've been doing the math on those pistons and if my numbers are right then they end up a bit down the hole and will need to have the block decked.

Unfortunately as far as I can see there is no off the shelf flat top piston that will drop straight in and come up close to zero deck, close enough to not require machining of the block.
 
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