The real question is what are you going to do with the truck. A daily driver, hell just put an LSA in it and be done. But then you have the issue of originality. There are some fast small blocks out there. A big block is not far off base, because the SS trucks had a 454. So the real question is, how original do you want to keep the truck. The value of our trucks is going up, day by day. Also an old school engine will be cheaper to do. In the end, its all about what makes you happiest.