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Darton makes a small bore and a large bore sleeve, or at least they used to. Not sure if anyone uses the small bore one anymore. There are repair sleeves if you want to keep the small bore.
This'll be my first build. Been hearing on gen 1 stuff for 25 years.
It's be a roots blown, mechanically injected, msd mag fired combo for a nostalgia racing category. Roughly 15-20psi expected. Needs to make around 1100hp
Last Gen 1 deal was 9:1, 4.125x3.625 and was hard to slow down too run our 7.60 index. 1975# combo.
Was considering a smaller bore, keeping it around 332 inches. 4.00" with a 3.268 stroke
There are three sizes of Darton dry liners all of which have the same external dimensions. The small bore version (300-023) is roughed to 3.875" bore, the middle version (300-026) is rough bored to 3.985", the large bore (300-027) is rough bored to 4.110". The small bore version is used mainly for NHRA stock class engines which are limited to .070" over stock bore, the middle for LS3 bore size and the large bore for larger displacement engines using LS7 based cylinder heads. The other thing you need to watch out for is the chamfer at the bottom of the sleeve. Even though the smallest of these variations, the 300-023, will go out to 4.185" bore, you will need to re cut the chamfer at the bottom of the sleeves to avoid damaging the piston skirts. Max. recommended bore size for boost or nitrous is 4.155". This to avoid head gasket failure.
Another thing, not all Gen IV blocks can be dry sleeved. Some castings are Gen III internally, for instance any front drive 5.3. You must start with a siameesed bore block. 12571048 is the one I used most often. Make sure there is no coolant passage between the bores just under the deck surface.
Originally Posted by GregM784
With darton sleeves in a factory gen 4 5.3 block, can it be bored to 4 inch?
Been doing searches, couldn't find a clear answer
I appreciate your help everyone.
A wealth of knowledge. Thank you very much. I'll see what casting my block is. That's good to know.
Just so you know, the gentleman who gave you all of that is the owner of RED in Oceanside Ca. He has been sleeving blocks for over 40 years and knows more about this process than anyone else. He owns several patents and does a ton of R&D for Darton. He does my sleeving. I trust no one else.
If weight is not a consideration, there are 2 main advantages to an aftermarket Iron Block.
6 bolt per cylinder for increased head gasket seal @ High Boost.
Priority Main Oiling for High RPM 7000+ RPM.
Iron Block is just inherently Stronger & More Stable.
I've thought about an aftermarket block. I'd like to stay away from iron for weight and inability to fix them. I've 86'd two Gen 1 Dart iron blocks in 10 years. We wont' see big boost numbers, maybe 20psi max. We race a 7.60 index class, so it's not very hard to get to that ET at less than 2k#
I don’t know and don’t pretend to know everything about a boosted build, but this much I do know...an LS block (OEM style) has 10 headbolts per side, while a Gen1 or Gen2 SBC has 17 head bolts per side. 20 pounds of boost and only 10 headbolts might work out, or might not. Doesn’t seem like a good idea to me personally. On the one hand, the aftermarket LS blocks, both iron and aluminum, are available in “6 bolt” versions, which have 18 headbolts per side. Overkill? Maybe. But I like overkill 99% of the time in everything except paying taxes.
I love the rocket your racing. The old school stuff is very cool to me, but I’m a notch away from being 50 years old, which is a whippersnapper compared to a few around here...
I've thought about an aftermarket block. I'd like to stay away from iron for weight and inability to fix them. I've 86'd two Gen 1 Dart iron blocks in 10 years. We wont' see big boost numbers, maybe 20psi max. We race a 7.60 index class, so it's not very hard to get to that ET at less than 2k#
I would lok at the Dart billet blocks and stay SBC. To swap to LS platform is a major cost initative. Basically you would have to change everything short of the blower itself. It's been said by a few real highend builders that the LS is not over and abve a SBC at the topend of the game. I think the head tech is way advancing over SBC, but the bottom ends are more/less equal. Think of it this way, the Dart LS next block uses a splayed cap just like their SBC. BTW, if you need them, I have a real nice set of new Carrillo SBC H-beams I am selling cheap.
I believe the 12569513 block is a 2005 - 2006 version. Siameesed 5.3 blocks started in 2007. As far as I know the only two castings that will work are 12571048 and 12601900.
Head gasket sealing is not a problem with four bolts per cylinder. Use ARP New Age 625 studs and Athena head gaskets. I used to rethread for half inch Viper studs. No longer necessary. The New Age are actually stronger.
Past 1000 HP it is a good idea to fit steel main caps.
Steve
Originally Posted by GregM784
The 5.3 block i'm considering for this build is a 12569513 block. I can't locate a definitive answer on if it's a Siamese block or not
I believe the 12569513 block is a 2005 - 2006 version. Siameesed 5.3 blocks started in 2007. As far as I know the only two castings that will work are 12571048 and 12601900.
I'm in NorCal and have a Callies Magnum 3.27" stroke crank and Howards billet rods if you are interested. Also an LSA block that needs to be bored over (factory piston squirters).
05-02-2021, 07:49 PM
Darton sleeves, 5.3 gen4 block 
