Once you've pulled the old Vortec engine from your '96-'99 GM truck or SUV, remove the parts needed for the crate engine to get it going in the vehicle. It's best to do this with the old engine on a stand and a table nearby on which to place the parts.
For those who want to step up the performance of their small-block V-8- powered '96-'99 GM truck or SUV, without making a ton of modifications, an easy answer awaits. GM Performance Parts (GMPP) now has a big-cube small-block, called the HT 383E, that will bolt in like a stock V-8 engine, meet emission requirements in most states, and put considerably more power to the ground. Last month we showed you how to remove your old worn-out engine, in this issue we'll show you which parts you need to install on the HT 383E. OK, we'll give the end away: the HT 383E engine produced a triple-digit power improvement to the tires, runs like a stocker, and the truck gets the same fuel mileage as before. Did we mention it was fun to drive, too?
Parts SwapProbably the least documented aspects to swapping a crate engine, in place of a worn-out engine, is knowing which parts to pull off the old engine for reuse, how to prep those parts for more miles, and how to determine what needs to be replaced before assembling them on the new crate engine. This sounds basic, but most enthusiasts are surprised by how often special tools, finesse, or knowledge is needed to get through this part of an engine swap. In this case, we were lucky enough to have the super-detailed Dr. Whaba R&R (Remove & Reinstall) Photoinstructions to follow throughout the process.
The install began by stripping the old engine by removing the dipstick tube (arrow pointing to where 3/8-inch bolt holds tube bracket on head), opening the clips on the spark-plug wire loom brackets, and then removing the bolts, which held the brackets on the engine.
Engine Drop-InGetting the GMPP HT 383E crate engine into the vehicle requires some heavy-duty tools, like an engine hoist, a floor jack, jackstands, and the help of a friend or two. After all the work to get the old engine out and prep the new engine, the reinstall didn't seem like such a big deal and went fairly smooth and fast. If anything, reconnecting all the wiring connectors was a lot easier than removing them.
Making It RunThe start-up and break-in of the new engine went smoothly. We did before and after chassis dyno testing and the HT 383E created impressive power gains in the lower rpm range compared to the stock 350ci Vortec V-8. For example, at 3,400 rpm, the stock 350ci made 111 hp and 72 lb-ft of torque at the wheels. The HT 383E bumped that to 183 hp and 118 lb-ft at the wheels-a lift of 72 horsepower and 46 lb-ft! You could feel this in the seat of your pants when tipping into the throttle.
After removing all four spark-plug wire loom brackets, we removed the six 9/16-inch bolts, which held each of the two exhaust manifolds on the engine. Making sure to save the four tin heat shields for reuse on the new engine, we also removed the three 9/16-inch engine-mount bracket bolts on each side of the engine and the fuel-pump blockoff plate. | 
Many of these GM trucks/SUVs came with quick-release connectors to hold the oil cooler lines on the engine. These are usually difficult to remove intact, so we pulled the top tip loose with a dentist pick pulling on the tip, then pulled the bottom tip loose (see arrow 1), and finished by hooking the pick under the clip and pulled it off (arrow 2). |
Here's what the worn-out engine should look like after being stripped of its reusable components. This engine should be drained of its oil and coolant before being returned as a core engine. We used an engine hoist and lift chain to remove it from the engine stand and placed the new crate engine on the stand. | |