does anyone know what the stock compression ratio is for a 2000 LD9 engine?
Nope.. All LD9 engines are 9.5:1 and that is direct from GM. If you use a pre 99.5 head on a post 99.5 bottom end you will probably be at about 9.7:1. The pre 99.5 head has a smaller chamber but a dish in the piston. The post 99.5 head has a bigger chamber but a flat top piston.
When did we figure out all are 9.5......it has always been said the 2000-02 are 9.7
and its always been wrong.
the proof is in the pudding.
how do you know its 10:1?
are your new pistons completely flat? if so since you have a 99-02 head you still have 9.5:1. unless of course you bored the block and installed SS valves in the head. in that case then yes, you may have 10:1.
A LOT of things make up the compression ratio.
block deck height
head deck / head year
head gasket thickness
valves
pistons
bore size
