For a junkyard/used turbo I think a Syclone & Typhoon turbo (4.3) is a good size for a 250= 4.1, Plus they have water cooled centers.
The Buick T-Type motors are smaller (3.8) & using one of those turbos will work, but will be more restrictive.
I have not measured a manifold inlet temps w/out an intercooler, but I have w/my Syclone that has a water coolded intercooler.
With just normal driving around @ night, approx outside air temps of 65 degrees (F) I see 90-95 degrees (F), and that is not boosting @ all, just driving normal.
I can imagine not having any intercooler, the air inlet temps would probably closer to 100-110 or more degrees in the same conditions, add 5 psi of boost pressure to that I can see the inlets temps getting pretty hot easily, I can only guestimate the temps (115 & up for sure, 160?, I would still recommend a intercoller of some sort, we still have all the under hood heat to deal with & dont forget the exhaust manifold is right under the intake manifold.
I dont buy into anyone suggesting not to use an intercooler, that's jusy my opinion.
Two cents thrown..
MBHD
