We set all of the required reusable parts on a large table, which helped to keep everything organized and in one place. Now was a good time to clean all the parts with some solvent and rags, scrape off any leftover sealer or lube, and prep the components for reinstall on the new crate engine. | 
Next, we placed the intake on two 4x4- inch blocks like this, which protected the injectors, then sealer was scraped off of the mating faces. Finally, we cleaned these surfaces with a 3M Rolo' cleaning brush spun on a grinder, then wiped it with solvent. An airgun was used to blow off debris in the ports. The 3M Roloc brush is best because it cleaned the surface without any abrasive. |
Then, the oil-pressure sensor and 90-degree fitting were threaded into the new engine block. A light coat of thread sealer was applied to the fitting threads, hand started and torqued to 11 lb-ft. We then did the same for the sensor, using an oil pressure sensor (OPS) socket to tighten. We made sure the fitting had the sensor pointing at this angle to clear the firewall. | 
The oil cooler fittings (shown) and lines usually leak on high-mileage trucks, so we replaced them. We ordered these from a GM dealer. The fittings PN 15529401, hose PN 12472279, and PN 12472280. Next, we installed the fittings by applying sealer to threads, hand starting them, and tightening them to 18 lb-ft. Clips were installed by pushing them into fittings with one motion. |
We clipped new intake gaskets onto the heads, then applied a 3/8-inch wide bead of RTV sealer on the engine block 'China walls' (see arrows), overlapping the gaskets 1/2-inch. Next, we installed the intake straight down and hand started the bolts with thread sealer on them. Torqueing the bolts in a radial pattern in three complete sequences to 27 lb-in, then 106 lb-in, and finally 11 lb-ft was the last step of the intake assembly. | 
Setting the rotor tip in line with the 'cast-in' No. 1 cylinder pointer on the 'flat' portion of the Vortec-era distributor body began the distributor installation. Then, we located the No. 1 cylinder piston at Top Dead Center (TDC) on the compression stroke by matching the timing pointer with the '0' on the harmonic balancer. Next, we clocked the oil pump driveshaft with a long screwdriver (see arrow pointing at bottom of distributor hole) to match the slot in the distributor shaft and installed distributor. |
With the new engine dressed with vehicle-parts, we hoisted it off the engine stand and rolled the hoist up in front of the vehicle. Lifting the engine over the radiator support and sliding it toward the engine bay was a cautious procedure. We slowly lowered it into the vehicle until the engine mounts seated in the frame mounts, then slid the through-bolts into the engine mounts and secured them, which completed the top of the engine service. | 
Maneuvering the engine and transmission together and hand starting the mounting studbolts got the engine into its home. The two studbolts on the driver side of the vehicle needed to be tightened with a wrench (a socket wouldn't fit around the floor sheetmetal). Various wires and brackets attached to these studbolts with 13mm nuts, and we installed them after torquing the studbolts to 35 lb-ft. |
We then pushed the torque converter against the flexplate and hand started each torque converter bolt before rotating the flexplate to the next bolt hole. Once all of the bolts were hand tightened, we torqued them to 45 lb-ft. | 
Next up, we positioned the starter-like so-and attached the power and starter wiring on the solenoid. These wires often become corroded and break off soon after an engine swap. So, we were careful with them and inspected them for trauma before re-installation. |
Installing the exhaust crossover tubing was next. We did this by pushing each end back up inside the three exhaust-manifold studs on each side. We then tightened the nuts (old nuts will probably take a 14mm socket, new nuts a 15mm socket) to 30 lb-ft in a radial pattern. Reinstalling the O2 sensor (see arrow) in the crossover tube was last. | 
Reinstalling the plastic top of the intake manifold, which is specific to the Vortec V-8 engine, was easy. The top has an O-ring nested in it that must be seated in the groove and cleaned before reinstall. We then torqued the 10mm studbolts in a radial pattern in two passes: first to 44 lb-in, then to 88 lb-in. |