is it 6.2 0r 6.5

[Stephen Tarry]

Hi Guys, New to the site and to GM Disels for that matter. Im in the UK by the way.
Just bought a Bayliner with a GM Diesel in, but she wont go over 8knts?
Its advertised as 195bhp but I have no idea waht it is to sort out the power issues.
Im trying to work out if its a 6.2 or 6.5 ?
The Block Cast number is 12552929 (drivers side)
and G274 (passenger side)

GM LD is also on the front of the casing
BL2A13CME889 is the only other number that may Id the engine.

Hope soeone can help

steve