a swap should be no problem at all... i seriously doubt the Poncho 400 is craving a blower after 20 years of use... my gut instinct tells me that (depending on the year, and if it was a car or truck 402) you should build the 400 to put in, and go naturally aspirated. there's a decent amount of go-fast parts available for the Pontiac 400, but the 402 i believe still beats it. what year 402 was it? i'd be interested in the bore and stroke compared between the two motors among others things.... i'll get back to ya more after this weekend regarding the two specific engines and comparing connecting rods, cranks, mains, flow etc.... to see truly which one is better...