I'd say you'd be better off dropping in a B230F-T engine from a
wrecked 740 turbo, because that engine is already set up for
turbocharging. To turbo your B21F and be able to use a decent
amount of boost on pump gas, you'll need to drop the compression
ratio, either by using the pistons from a turbo, or by using a much
thicker head gasket. I've also heard that the turbo's valves are
sodium-filled for better heat transfer so as to minimize the risk
of burning valves.
.
If you do go ahead with this project, I suggest using some variant
of Bosch LH-jetronic injection - ideally 2.4 or 3.1 because the
2.4/3.1 computers have self-diagnostics built in. It's also
pretty easy to install the APC (automatic pressure control) system
from a SAAB 900 turbo when doing a turbo install. This system
incorporates a knock sensor which cuts back on boost when knocking
is detected, which could save your engine from damage. The APC also
has an adjustable RPM-boost curve.
.
You might also want to try www.turbobricks.com for more advice.
.
-b.