block max. bore

I need an experienced builder to give me there opinion on the max. bore on this D9 block used in a n/a motor with around 800hp. the block is already at 4.420.

I recently purchased a sonic tester and I'm trying to find a block that will go 4.5 bore. I'm trying to get a feel for things when sonic testing a block and what results I need to be looking for.

strokedmyford wrote:I need an experienced builder to give me there opinion on the max. bore on this D9 block used in a n/a motor with around 800hp. the block is already at 4.420.

Looking at the numbers, especially on the major thrust sides, it looks like you would be good for another size increase to 4.440, but that would be it unless you fill the block.
But what do I know....Im just trying to get my own junker running too!!

Don't forget to first calibrate your sonic tester for cast iron or your results might be a little off. Use some point on the block that's easy to verify the sonic testers numbers with using dial calipers or a micrometer (IIRC the main caps, or the china wall, or ???).

BBFTorino wrote:

strokedmyford wrote:I need an experienced builder to give me there opinion on the max. bore on this D9 block used in a n/a motor with around 800hp. the block is already at 4.420.

Looking at the numbers, especially on the major thrust sides, it looks like you would be good for another size increase to 4.440, but that would be it unless you fill the block.
But what do I know....Im just trying to get my own junker running too!!  

I'd agree with this, but also add a half full won't hurt either.

Next size doesn't have to be another .020 either, with custom Pistons you can just hone out the wear too.

That would be your best move.

Bore it however much will get you a decent cylinder and call it a day. You don't get that much power out of the bore size increase anyhow.