only if you are changing the diff because of different ratios. if the ratios are the same then you dont need to change the speedo or the diff.

you dont have to change the speedo or diff even if they are different but i would. generally with a larger engine the factory would fit a higher gear ratio so the engine turns less on the highway. this mitigates the extra fuel required by the larger engine and makes the car quieter at highway speeds.

if you are planning on drag racing, towing heavy loads or live in mountains, then you might keep the (presumably) lower gear that the 230 prob has.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.