Compression ratio

[69candy]

Just about to order a new set of slugs for my 428, but the size I want, 40", I can only get 10.3 to 1. This should be ok with premium fuel shouldn't it?? I can get 9.5 in cast but not forged without breaking the bank!! Last piece of my puzzle!!

[jiffy]

So, there is a guy on the CJ forum who makes custom pistons - whatever size, whatever compression, so it might be worth talking to him, let me know if you want his details.
10.3:1 is plenty, and you might find your cam specs change the actual compression ratio a little (I think you've posted on this elsewhere) but it will give you all you need, and still leave a little head room - especially as you're planning on using aftermarket heads IIRC? Likely to have a better combustion chamber shape that will avoid detonation. Originally they were 10.6:1 but with your heads/cam you mightn't get that anyway, and if you NEED 10.6 then skim the heads with the 10.3's in there.

Just make sure you use 98 Octane whenever you can...

[shaunp]

Mid 10's are ok in Windsors with alloy heads, they still take plenty of timing with 98, but that's with alloys. You can always stick a thick head gasket in it if you want to drop it a little.