[truckster]

I love the Olds 455 (I never had a 400) and I've put one in a Chevy. Yes, it can be done; it will definitely be more expensive. Mine was really fun to drive and I loved it except for the fuel mileage. If you want something different and you're up to the challenge, go for it. BUT...

What makes you think the 327 is too small for your truck? I had a 64 C10 with a 283 and it moved just fine. Now, if you really just want to spend more money or plan to do a lot of towing, or you just want bragging rights the 454 might be the thing for you. But a properly built SBC is going to move your truck around smartly, and it's going to cost less to build and operate.