My friend bought this kit off ebay to rebuild the engine. http://cgi.ebay.com/ebaymotors/ws/eB...BSAA%3AUS%3A11

Need advice on how what to bore it to and the compresion ratio that should be used.

Going to be a turbo setup.

 

you can only go with an 82mm bore on the stock sleeves. and since he'll be going turbo i wouldnt recommend that. he'll need to resleeve it, which is going to be another ~$1000 then bore it to whatever he wants. i'd recommend 83mm so he has room for a re-bore if the cylinders ever get messed up. dont go above 10:1 c/r for a boosted setup.

tell your friend, instead of having bought this kit, he could have just bought the rods and pistons individually, all new bearings, and come out cheaper than what he paid for it.

 

10:1 will be fine with even an 81mm stock bore for the street. If you wish to go higher on the comp ratio, don't expect to benefit on the street since you'll likely have to retard the timing.