If you’re a regular reader of All Chevy Performance, you’ll probably recognize our ’57 Chevy 210 wagon that we’ve been building in the Clampdown Competition workshop for our buddy Bruce Valley. So far, we’ve replaced the front and rear suspension and added power steering, among other things. We also did a serpentine pulley system install on the LS3 Connect & Cruise engine kit in anticipation of its installation between the ’rails, which is where we’ve now found ourselves.
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The carbureted 350 in Bruce’s wagon was a solid runner, but the allure of an LS swap was too much for him to resist. With the increase in reliability, driveability, fuel economy, and performance, it’s an easy sell if one’s budget allows, and for Bruce, the replacement of the existing Muncie four-speed manual trans with an automatic overdrive will make for a more relaxing commute.
For a quick recap, Valley wanted to upgrade the old wagon with power steering, A/C, and an overdrive transmission. Quickly going over what was involved to make said upgrades to the existing 350ci small-block Chevy/Muncie four-speed combo, it was an easy decision to shift gears and proceed with an LS upgrade. Since all the components needed to be purchased, whether the 350 was used or we went the LS route, Valley was quickly convinced that what he really wanted was a more comfortable, reliable, user-friendly experience, with whatever that required—which meant we were going the LS route.
We opted for the plug-and-play solution that Chevrolet Performance offers in the form of their Connect & Cruise LS3 combination. This package will make adding air conditioning and power steering, two of Valley’s requested caveats, in addition to an automatic, four-speed overdrive transmission via the 4L65-E transmission, possible.
With that in mind, we recommended the Chevrolet Performance Connect & Cruise LS3 package. Rated at 430 hp, the 6.2L powerplant would be more than capable of hauling Bruce’s big wagon around town, and thanks to the 4L65-E transmission and its 0.70:1 final drive, it will be even more suited to efficiently cruise down the highway than with the old Muncie. Years of use and millions of miles traveled in nearly every marque made by GM make the LS and their relative electronic components dead reliable when compared to the electronics of yore.
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Before we get too ahead of ourselves with the engine swap, there are a few things that need to be addressed on our new LS3 engine: For starters, the stock oil pan needs to be swapped out for a rear sump version that will clear the steering centerlink and front crossmember.
Convinced of the value of the LS swap, we still needed to figure out what it might take to put that modern powerplant between the ’rails of a nearly 70-year-old car. As luck would have it, we weren’t the first to attempt this swap (big surprise!) and companies like Classic Performance Products (CPP) and Summit Racing have everything one needs to achieve a fully bolt-in installation of a modern GM powerplant. By using a combination of stock engine mounting hardware and adjustable LS engine plates, not only is the installation a bolt-in, but it’s a fully adjustable bolt-in as well, making precise engine placement possible. These components make what would be a more advanced job saved for the mechanic with a fairly decent degree of fabrication possible by a guy with a little mechanical ability and a decent set of hand tools. It’s never been easier to swap a modern GM engine in a classic muscle car than it is today, and we’ll prove it!
Removal of the stock oil pan and pump pickup are the first order of business. Then the provided rear sump oil pump pickup can be installed …
… followed by the Summit Racing Pro LS cast-aluminum oil pan (PN SUM-121200). Note the difference in size and dimensions between the Summit pan versus the stock LS3 GM pan in the background. The Summit Pro LS pan features a rear sump that is slightly deeper but shorter than its stock counterpart and offers increased clearance at the front of the pan as well.
The stock 168-tooth, 14-inch flexplate is installed and torqued to the LS3 crankshaft …
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… while the matching torque converter is installed in the transmission. Prior to installation, the torque converter has been filled with 6-8 ounces of Dexron VI trans fluid to prevent a dry start-up situation that could damage the internal components of the torque converter, pump, and related components. Installation of the torque converter is accomplished by pushing it onto the input shaft of the transmission while slowly turning it as well. Two steps should be felt before the converter is successfully seated into the pump; the stator shaft and the input shaft.
Properly installed, when the engine and transmission are mated, at least 0.125-inch but no more than 0.250-inch of clearance between…
…the flexplate and the mounting face of the converter should be observed.
If everything is within spec, the three torque converter to flexplate fasteners are installed and torqued to 37 lb-ft.
Mounting the engine securely to its frame is accomplished by a combination of engine mounts and brackets. Early style small-block Chevy engine mounts (PN SUM-7731114) from Summit Racing should be recognizable to all Chevy muscle car fans, but their Adjustable LS Conversion Engine Mounts (PN SUM-7731100) and CPP’s Engine Mounts for ’55-57 small-block Chevys (PN CLP-CPP5557SMFSB) may not be.
Summit’s Adjustable LS Motor Mount Adapters allow for up to 3 inches of adjustment, fore and aft. They are adjustable to position the bellhousing in the stock location …
… 1-inch forward …
… or 2 inches forward. Each position has an additional 1/2-inch worth of further adjustment. The plates have been designed to retain proper driveline alignment regardless of mounting position.
Transmission mounting will be achieved by a bolt-in CPP Tubular Transmission Crossmember (PN CLP-CP90044).
We covered the engine bay detailing story separately, but here’s a reminder of how it turned out and what the engine compartment looked like before the LS install began.
CPP’s engine mounts allow for the placement of a small-block Chevy engine ¾ inches forward from the stock location.
These bolt-on mounts utilize existing holes in the Tri-Five’s crossmember to locate and secure the mounts while an additional four holes will need to be drilled using each mount as a guide.
Here, the three engine mounting components are loosely installed, awaiting the engine.
With the transmission bolted in place, slipping the engine into its cradle can be tricky, but with the right help and equipment anything is possible.
Our LS3 Connect and Cruise powerplant is set in its new home.
With the mounts adjusted to the furthest forward position, we noticed that there was plenty of room between the bellhousing and the firewall, while the real estate at the front of the engine was getting tight.
It was decided to move the engine back as far as possible toward the firewall, while still retaining plenty of room for access to sensors, fasteners, and so on.
This resulted in the engine located roughly 1 3/4-inch forward from stock; an inch thanks to the adjustable plates and an additional 3/4 inch thanks to the CPP engine mounts.
This angle shows the assembled engine mount components in place.
Here, we can see the clearance achieved by the Summit Racing Pro LS oil pan between it and the steering linkage…
…as well as the front crossmember.
Out behind the transmission, we set our attention to the transmission mount. First, the CPP transmission crossmember is loosely attached to the transmission mount and the trans checked for center between the framerails.
The transmission mounting brackets are attached to both ends of the crossmember and checked for even alignment with an existing feature on the stock frame.
Once square, holes are drilled using a 5/16-inch drill bit into the frame to accept 3/8-16-inch thread forming bolts.
With the transmission mount secured, the drivetrain installation is complete.
The stock wiring harness for any LS engine leaves quite a bit to be desired when it comes to keeping things tidy under the hood; and that terrible plastic loom is only the beginning.
Laying out the wiring harness on the engine, it’s easy to route the different connectors to their respective sensors, but it’s still a bit of a mess.
Part of the LS Series Crate Engine Control System is the brain behind the engine, the engine control unit (ECU), a pair of O2 sensors, and a mass airflow sensor.
The transmission control system is a similar “sack of snakes” when it comes to the wiring, although not nearly as complex. It consists of the transmission control unit (TCU) and wiring harness.
Due to the relatively limited space in front of the engine and for ease of installation, we opted to utilize a Concept One Mass Air Flow Sensor Housing Kit (PN A80530KM). This adapter housing is designed to mount the Mass Air Flow Sensor directly in front of the throttle body and accepts an Edelbrock air filter. We dig the clean look and the lack of plastic tubing snaking around the engine compartment that most air induction systems consist of.
After removing the offending plastic loom we set out rerouting the ECU/TCU as well as the fuse panel wiring harness as required on our application. All three components will be mounted atop the passenger side wheelwell, so a pair of bases were made for the ECU and TCU with a set of adapters to mate/stack the two together.
The fuse panel will attach using a pair of Summit Racing Fuse Box tabs (PN SUM-900485) that will allow easy fastening of the fuse panel to the inner fender.
Here’s the complete wiring harness after a retape and bundle in braided split loom.
The ECU/TCU package sits inside the fender from the fuse panel and all the wiring disappears deep into the fender and under the kick panel, out of view.
The entire engine harness received the same treatment, included the fuel injector and coil pack harness. Our LS3 is fully wired and ready to make loud noises without a giant mess of wiring. Note the installed Concept One Mass Air Flow setup as well as their serpentine pulley system we installed in a separate story.
