A suggestion to make thing easy, GM has a EPA approved upgrade engine for S10s that originally had the 2.8. It's a 3.4 liter (207 cid) engine, same bore and stroke as the 4 cam engine, but uses the std heads and block. It's a bolt in engine, no cutting, odd mounts, and will bolt up with the existing trans. It should have plenty of power and decent economy, too. It's GM part # 12363230. Rated at 160 hp and 194 ft/lbs. It only needs the intake, ignition, exhaust, water pump (and belt drive) and an electric feul pump to install.
BTW, I've never seen a turbo Quad 4, and from my own experience, they are a very doggy engine, even in a light weight front driver.
