There is no Pontiac Stratostreak V8 that can be dropped into a stock chassis with long tube headers attached that I'm aware of, and I've worked on a lot of different Pontiac cars with headers.
To start with the Pontiac engine is very wide from exhaust flange surface to exhaust flange surface. It has a wide, and deep oil pan, and the exhaust exits at a 45 degree angle from the cylinder heads, all eats up a lot of under hood real estate.
It's no SBC dimensionally, and that is probably the only GM engine that may be able to be installed with long tube headers, and even having a small oil pan sump and being much narrower than a Pontiac, it still may not fit all applications.
Side by side comparison shows what I'm speaking about
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Those cylinder heads really make your butt look big........
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