see i like the 347 idea for power, but with gas prices getting to 2.67 a gallon, the 4.6 sounds a little better, they can still make a lot of power.... the 351w on the other hand sounds great, but to get one ina 66 mustang, i have to bang the shit out of my shock towers and use custom headers designed for the swap.... and as i hear, getting the spark plugs in and out is a real PAIN in the ass