The Chevrolet 305 cubic inch V-8 engine has been used in many cars and trucks since the late 1970s. Chevy's 350 CI engine, with nearly 50 cubic inches more displacement, has been in produced since 1967, and produces more horsepower and torque. Dimensionally, both engines share the same external measurements and fixtures for accessories. Swapping to the larger, more powerful 350 engine is simply a matter of disconnecting and lifting the old engine out, and re-installing the replacement 350 engine. The only potential consideration is whether or not the vehicle has any computer controls, and if they need to be converted.
Park the vehicle in a workspace with plenty of room to work around the front and both sides of the vehicle. Disconnect the battery cable. Secure the vehicle by engaging the emergency brake and/or blocking the rear wheels. Remove the hood, and jack up the front of the car/truck, placing jackstands under a secure part of the frame.
Remove the torque converter cover from the transmission. Loosen and remove the three converter bolts that fasten the converter to the engine flexplate. Wire or secure the converter, so that it remains in the transmission. Remove all bellhousing bolts that connect the transmission to the engine block. Remove the starter cables from the starter. Unbolt the exhaust pipes from the exhaust manifolds. Remove the through-bolts that fasten the engine mounts (one on each side of the engine) to the frame mount.
Disconnect any other cables, wires or hoses that are accessible from beneath the car, and which would prevent the engine from being freely lifted out. Remove the jackstands, and lower the vehicle back to the floor/ground.
Remove the radiator shroud, and drain the engine coolant into a catch pan. Disconnect all electrical wires, hoses and/or cables between the engine and firewall and fenderwells. Remove the air filter assembly and any cowling. Attach a chain or lift cable to the top of the engine at the front intake manifold bolt, and opposite-side rear manifold bolt. Place a jack or support underneath the transmission.
Roll the engine hoist/lift into place at the front of the car, and hook it to the lift cable/chain. Slowly lift the engine up while simultaneously lifting the transmission. (Be certain to gradually lift the engine and transmission together.) Once the engine has been lifted enough to clear the engine mounts, the transmission should be fully supported. Roll the engine lift forward (away from the transmission), enough to be lifted up and out of the engine bay. Roll the engine to an area next to the replacement engine.
Swap any engine parts from the old engine onto the replacement engine. Typically, the original exhaust manifolds, engine mounts, water pump and other engine components will be swapped unless it is a complete engine assembly from a similar salvage or donor vehicle.
Attach the engine lift cable/chain to the new engine, and roll it into the engine bay. Carefully and slowly lower the engine into place. Align the rear of the engine with the transmission and slide the two together. Lower both the engine and transmission into their final position, and make all connections and attachments in the reverse order of removal.
