I have not used any of thosse cam in a big block before but I have used the 268xe and the 280h in a small block. I built it with the 268 then he decided he wanted something bigger and i had a 280h laying around. the differeence was night and day. Now he cant even hook up in second gear if he floored it. and this is in a 4door chevelle w/275 tires.