Since the 70's, Buick, Olds, and Pontiac traditionally share the same blocks, internals heads etc.. every GM shared the same tranny's and diff's though. I'm unsure if the adapters will work. I know the motor mount locations are different between the Chevy and B.O.P small blocks.
All FOMOCO parts are pretty much interchangeable between manufacturer. Dodge is the same way. AMC was a bastardization of all the big three!
Now only if I can put a 5.0 and 5 speed in the 62 with a kit I'd be happy!
Around 79 or so GM started going to a corporate engine and driveline. I think the Buick 350 was one fo the first of the "old school" GM 350 engines to stop production. A buick 350 is clearly a different engine than a chevy engine. What would concern the poster is the bolt pattern for the trans mount. There use to be a Chevy 350, a olds 350, a Buick 350, and a Pontiac 350?.
The corporate GM V-8 that was shared among the cars...was a Chevy 350 and 305 for the most part. There were some Olds 307 engines in Cadilliacs, there was olds 403 in the trans am. Then you saw the chevy 350 in cadiallacs.... All the other GM divisions stopped making V-8s and Chevy is the only manufacture of the corporate V-8. Not counting the NorthStar V-8, or the other oddball cadillac V-8, 4.1 Liter (front wheel drive V-8)
There are clear differences between a buick V-8, an Olds V-8, Chevy V-8, and a Pontiac V-8... the common item is that most will bolt to the standard GM 350 transmission. There is very little that is interchangeable between the various divisions V-8 engines.
If you are going to put a GM V-8 engine in your truck, you will be far better off to use a Chevy V-8. Think about the difference in brackets, intakes, heads..etc (finding parts)... THere is a proven path forward with the Chevy V-8. I can't say I would even consider any other V-8 engine, for the combination of parts, known design, known parts configuration, and plenty of others who have done the same thing. If you wanted to run old school...you could eaisly run older style Chevy V-8 with Carb, for not much money at all.