Brett240

with the L24 Block you use the diesel crank, shorter L28 Rods, L24 Pistons and a P90 Head. you get 2694 cc and 10.03:1 compression

i had a very similar problem a couple of months ago. a vibration occured above 45 miles an hour only when accelerating, at first i thought it was the fly wheel coming loose:( but it turns out that the tailshaft was coming out of balance. after a couple of quarter mile runs at the local strip it was so bad i had to tip toe home. one balance job and two new universal joints later (even though they looked OK) and the car is the smoothest its ever been. hope this helps

boring the l24 block to 86mm shouldnt be a problem, but Ed is right, the l28 block is already at 86mm, and you can bore them to 89mm, fit KA24 pistons and a standard l28 crank and get 2949cc.