Based on the 56 OMC engine builds here in Canada a good drag motor would be oval port sleeves in a 1986 production cast block, mod 50 flywheel, Kevi baseplate and tuner, SST 60 gearcase with hooper billet carrier and 2 cylinder gears, a 12 1/2 X 24 thru hub Hill prop on a 13 foot Allison. Tuff to beat in 600 feet.