if you're going to put 89mm slugs in it you may as well go all out with the rest of the motor. the last L20 i had built had 89mm toyota flat tops, but they "fly cut" the tops of them for some reason, i'm no mechanic. spent $135 on a nosmo head gasket ( this was in 1994!) balanced, shotpeened, full floating gudgeons and a 75 degree works cam. i think from memory it cost me around $2500 ten years ago, but was money well spent. it certainly was one nasty little motor and still is putting down 140hp at the wheels of a 180b wagon. it pays to do it properly once.