[streetstar]

Depends on what you want to do with your truck---- you can build a 450 horsepower big block for less money than it takes to build a 450 horse small block. a 450 horse BB can be in a relatively docile state of tune, while 450 out of most small blocks is "on kill".

If you want a weekend toy and don't mind putting up with 9-10 mpg, then a bb beats a sb hands down for a full size truck. But not a 402 or a 396. Its just as cheap to get a 454 and a stroker crank from Scat is about $300 (give or take) and will take it out to 496. In fact, in today's world , the only reason to use a 396 or 402 is if its free and its all that you have - or if you are restoring a numbers matching vehicle.

But if its a grocery getter - the small block has a few cost advantages - but don't expect gas mileage to be a helluva lot better unless you are a tuning whiz.
I am trying to swap a 305/overdrive combo into a truck for better mileage(working on it now- waiting on parts, got some really good info in another thread i started called "mileage motors"from a few members) , the 350/th 350 combo in it was only good for 10-12 mpg itself