We survived the “nothing fits” portion of this late-model swap, though certainly without a good bit of frustration. While the GM Performance Parts H.O. 350 we selected does bolt to the stock engine mounts and transmission, that’s pretty much where the “bolt-in” part of the swap ends.
In this installment, we’ll walk you through our upper-engine trials and tribulations all the way up to installation.
After we fabricated new brackets to hold the engine’s electronics and cables, we were able to bolt on the intake manifold. Well, almost able to bolt on the intake manifold. It turns out that the H.O. 350 actually requires different bolts, something that our friendly GM technician assured us wasn’t the case. In fact, after numerous calls to several “accredited” GM Performance Parts dealers, we consistantly received the same answer: The part number’s the same as the one for the standard engine.
Note: Click on photos for larger versions.
So, we broke down, pulled out the press credentials, and contacted GM Performance parts directly. A very nice engineer returned our call, did some research, and came back to us with a correct part number. (Drop us a line if you’re doing this swap and would like the specifics.) We then took the part number to our local GM dealer, and they ordered us a handful.
Armed with the correct bolts, we were able to install and torque down the manifold, which allowed us to begin installing everything connected to it — specifically the throttle-body injection (TBI). The TBI bolted up easily, though the new intake manifold layout did give us a few headaches locating the electronics to where they reach easily; a little bending and prodding of the brackets solved the problem.
As we wrote about in previous “find” posts, we ended up acquiring a couple of extra tools to remove and install various plugs in the block, heads, and intake manifolds.
The remaining accessories bolted on nicely with no major issues.
For those who haven’t performed an engine swap before, you may not realize how magical it is to finally fill the big hole you’ve been staring at throughout the job. We were pretty excited as we rolled the Yukon outside the shop to get extra clearance for the lift. Besides the normal excitement, we were also looking forward to seeing if our custom mounts would hold the weight. (They did.)
Using the same crane we used to remove the old engine, we picked up the shiny-new H.O. 350 and lofted it over the Yukon’s nose and into the bay. This process was vastly simplified by a humble $40 load-leveller which we picked up from Harbor Freight. (Hey, it was rated for 4,000 lbs so we figured it’d do fine with less than 1,000 lbs of engine.) The leveller provides two end connections for your load, then allows you to crank the “hang point” of the load on the lift forward and backward over about a foot of distance. The leveller bar tilts with the load shift, so essentially you can crank the “pitch” angle of the engine up and down to maneuver it.
In our case, we ended up tilting the nose of the engine up a good bit, which allowed us to see as necessary to maneuver it into a good mate with the transmission. Once we had it positioned, we cranked the nose down slowly while clearing away any stray wiring, then seated it firmly into place on the engine mounts. The leveller came in handy again as we were able to lift the nose only a little to line up the engine mount bolt holes perfectly.
With the engine bolted in firmly, we rolled the Yukon back into the shop and began to install the shelf-load of waiting accessories and other parts such as the power steering pump, radiator, etc.
Having worked on literally every single part of the engine compartment, we figured we’d have at least one major setback when first starting the new engine, but it looks like we were wrong. On our first crank, it didn’t start, but after a few quick tweaks to the static timing, it cranked right up.
While the engine runs, it doesn’t run well — the stock computer is more than a little bit confused as we dropped an entirely different engine underneath its sensors. While our stock injectors can provide the necessary fuel flow, we believe the computer isn’t commanding it. We also still have some timing issues and a couple of computer codes to check out.
So, in our next installment, we’ll run down the tuning process.