i saw a 4.25" SBC crank on the holley website. i was just wondering how much machining and work on the block it would take to make it work? what else would you need to do? do they make pistons you can use with 6.125" rods you need to use with a stroke like that? just thinking...

 

You would have to have an aftermarket block to make it work.

 

You would need an aftermarket tall-deck small block.

 

GM ROCKET BLOCK!!!!!!!!:hail: :lala:

 

Definitly the rocket block. Once your done, there's not much else left to consider calling it a SBC.

Don't forget that you're trying to feed a SBC that's the size of a BBC with tiny SBC heads. An engine like that would have to have a supercharger just to be able to force enough air through the heads.

 

heh, bout time i was right...

 

Motown block would be a better choice for the money. That's what I plan on buying

 

Motown blocks are excellent peices, but would not work for this. It has to be a tall deck block with raised cam location. The Motown is standered heigth.

 

The Motown block can be bored out to 4.200". Using a standard 3.75" 400 crank only gets 415 CID. If it was possible to stick in a 4" stroke crank then it only jumps to 443 CID.

It's not possible to get that much displacement from a standard height block. You need to buy exotic parts or just use a BBC.

 

The motown will execpt a 4 in. stroke crank and also the 4.20 bore and still have room left to be safe. Like you said that makes 443 but that is still an sweet small block. Bill Mitchel is now offering a 443 crate motor for around $15,000.