440 .60 over?

[drobertson]

I got a 440 awhile ago, and upon cleaning one of the pistons, it was stamped ".40". The block had a little rust, and I want to know whether or not it's safe to go .60 over. The block is a 1974 Casting. Do I need a different block or should I just sonic check 'er and go from there?

 

[terzmo]

.060 is about as far as it goes

 

[moper]

Sonic test it and see. Chances are it's fine assuming the bores clean up at .060. If you plan to go bigger, personally I prefer to find a virgin bore to start with, but again - sonic test it.

 

[Cranky]

Sonic test it and see. Chances are it's fine assuming the bores clean up at .060. If you plan to go bigger, personally I prefer to find a virgin bore to start with, but again - sonic test it.

2nd that.....spending the money on sonic testing is well worth it. It also depends on how much power you are wanting to make with it. If it's a little bit thin, building a mild engine will probably be ok but making a 600 hp beast may not be ok.

 

[64 Post]

Another vote for sonic checking. Thin spots may not be an issue depending on which axis they are located.

 

[Cranky]

Right....it's usually not so much as having the whole cylinder thin but core shift is usually the main problem. I've found blocks that were plenty thick 3/4's the way around and be thin on the thrust side....that you don't want.

 

[drobertson]

Thanks all, the bores are pretty straight, and have no ridge at the top. The engine was rebuilt, then ran for 5k miles, and then yanked to sit in a field for a long time. I might just be able to hone it, and keep it at .40 over. I will be sending the block to a machine shop soon to have in cleaned, sonic checked, new cam bearings installed, and honed. Maybe bored if necessary. Goal for this engine is 450-550 horsepower. The machine shop nearby has an engine dyno, and I'll have it tested after assembly. I might have them assemble the bottom end, then I'll install an edelbrock top end kit and a tci or b&m transmission capable of the torque output.