Welcome to part two of our 5.3 LS conversion of a '55 210 sedan. In part one, we covered the actual installation of the engine/trans combo, gas tank, and cooling system. In this installment, we'll get to all the peripherals, stuff like plumbing the fuel system, wiring harness install, exhaust system, gauge cluster, trans cooler lines, and more. Then we'll turn the key on our salvaged 5.3L/4L60E truck powertrain, strap it to the Dynojet to see what the hard was was worth.
This particular swap, while involved, isn't that much different than a car seeing a standard Gen I V-8 conversion. We can hear some of you looking at us funny right now after reading that statement, but really think about it. Even with a Gen I-powered car (or especially a big-block for that matter) you're probably going to be replacing the wiring harness, having to re-plumb the fuel system to support your engine's power level, some sort of late-model trans, overhauling or upgrading the cooling system, and so on.
The added benefit here is you're going to have LS-based V-8 power under the hood. The owner picked up this salvage combo for $600, less than the cost of a rebuilt Gen I engine and a good, useable 700-R4. And be honest, if you pulled a 100k mile plus Gen I out of a junkyard (if you could even find one) would you just drop it in without touching it, or go ahead and rebuild/refresh it? We didn't touch the 5.3L except for the oil pan change. The heads never came off the engine and we knew from the yard the engine had over 100k miles on it. And with some basic bolt-ons and a cam change, we can have this thing cranking out over 400 horsepower, while still having an amazing cruise range. This is one of the many things that make these engines so popular.
Anyway, let's get on with part two!
01. Greg Lovell, the owner of the ‘55 that's the subject of this story, welds together a proper 2.5-inch exhaust for the 5.3.
02. Part of our CPP LS conversion kit was this oil pan (with necessary pickup) that will clear the front crossmember of most '55-up GM cars, except for '62-'67 Novas equipped with factory steering. A solid piece of cast aluminum, this pan is a lot stronger than the old stamped steel pan of Gen I and II small-blocks, and because it's aluminum it helps with heat dissipation from the engine oil.
03. For exhaust, we went with Flowmaster's 2.5-inch American Thunder kit (PN 817174). It fits both Tri-Five sedans and hardtops (not wagons or ragtops, though) and features pipe from the headers back (included in the CPP swap kit). The mufflers feature the classic Flowmaster sound, so the LS will have a deep, throaty rumble. The kit features full stainless steel construction, and comes with all the necessary hangers and band clamps needed for installation.
04. The H-pipe assembly in the kit features some extra length on the header side to allow for different V-8 and header installs, so it requires some trimming for an exact fit. We mocked everything up and used an Eastwood 135 MIG welder to tack the system together and mock up the hanger locations.
05. We welded the rear exhaust hanger tabs to the floorpan. This gave the mufflers the most solid support while clearing the driveshaft.
06-07. Once we had everything mocked up and were happy with the clearances, we fired the MIG back up and finish welded the pipe assemblies together where required, and used the included band clamps for the rest of the couplings so the system could be removed later for any future work on the car. Part of our CPP conversion kit was a transmission crossmember compatible with late-model transmissions. Its design provides clearance for the exhaust piping, and it can be mounted in multiple locations on the frame to accommodate a variety of different transmissions.
08.The car's original wiring harness couldn't handle the demands of running all the new electronics, and trying to sandwich in another harness on top of it just for the LS made no sense. Instead, we called Painless Performance and picked up its LS1/4L60E integrated 26 circuit/7 relay harness for use with a mechanical throttle body (PN 60608). This harness allows for the use of the stock GM computer, so tuning the engine itself and adding any performance mods and tuning are a piece of cake later on. Besides running the engine and trans, this harness also is equipped with everything else necessary for the chassis/body. It comes with all the necessary electrical connectors and plugs for setting the harness up. The only thing you'll need is a good wire crimper, and some patience.
09. One the left is the factory fuse block, and on the right is the new Painless Performance fuse block. Besides all the necessary circuits to run the engine and electronic trans, the Painless harness gives you all the extra circuits needed to add future accessories like power windows, air conditioning, a modern stereo system, and more.
10. We mounted the fuse block in the same location as the factory one, so running the harness to the engine compartment, ECU, and body were easy. All the wires in the Painless harness are marked for their purpose, so there's no guessing about what color wire goes where.
11-12. We used our hole punch to make a hole in the firewall so we could run the ECU wiring to where we mounted it on the outside of the firewall. Once we've got all the wiring set in place, we'll wrap it with Painless' PowerBraid wire covering to protect everything. PowerBraid is offered in different diameters and lengths to accommodate different lengths and bundle thicknesses of wiring. It's cut and abrasion resistant, while offering enough flexibility to make installation of it and the wiring easy.
13. For gauges we went with Dakota Digital's VHX cluster for '55-'56 Chevys. Controlling the cluster is this ECM box. An advantage of the VHX system is you don't have to run a mass of wires up to the gauge cluster area.
14. We mounted the ECM for the cluster under the dash, then ran the appropriately labeled wires into the box. From there, it's just a matter of hooking up the two fiber optic data cables to the gauge cluster and the passenger-side clock. We'll have more on the capabilities of the VHX system for our '55 later in this story.
15. The Painless harness includes this mounting bracket that holds the OBD II plug for the harness, and a check engine light to alert of any trouble. Since our VHX gauge cluster interfaces with the factory computer, any engine issues will be alerted through the cluster's information display, just like in '99-up GM trucks and SUVs.
16-18. We hit the local parts store and picked up an assortment of AN fittings, solid steel line, and high-pressure fuel injection hose to build our fuel system with. We worked three separate fuel filters into the system, including a factory late-model truck filter compatible with the return system, so even if we got a really bad batch of gas, it wouldn't give our engine a heart attack. We also installed a Summit Racing one-way check valve to prevent fuel drain back (PN SUM-220192B).
19. For an accessory drive, we went to Chevrolet Performance Parts for a system that would work with our future plans for the '55, (i.e., power steering and air conditioning). We selected accessory drive kit, PN 19155067, which we can use sans power steering pump and A/C compressor until we're ready to install those parts. This system is stock for C6 Corvettes, except the ZR1.
20-21. For throttle control, we hit the Lokar catalog and picked up Lokar's LS1 throttle cable (PN XTC-1000LS1), Tri Five Chevy billet gas pedal (PN XBAG-6074), and LS1 linkage cam (PN XTCB-40LS1). We also snagged Lokar's 4L60 floor mount shifter (PN FMS64L60GM). The shifter is the perfect height, and clears our factory bench seat even when placed in First gear.
22. On the ignition side, we decided to do a total refresh, and installed ACCEL's LS coils, spark plugs, and ceramic-booted spark plug wires. We had previously installed a set of these wires on a C6 Corvette and picked up 10 horsepower just from the wires over the set of aftermarket performance wires the car already had. We also installed a set of ACCEL Performance 48 lb/hr fuel injectors. We also added a set of Holley's polished LS valve covers to brighten things up and provide a nice contrast to the yellow ACCEL coils.
23. For the transmission cooler lines to the 4L60E, we hit the parts store again and got some 3/8-inch steel lines to build everything so we wouldn't have any rubber transmission lines on the car.
24. Here's a cool item. With the Painless harness and 5.3L truck engine, we were able to keep the factory '55 battery location, and the stock battery cables for a C6 Corvette fit perfectly.
25-26. The last step before turning the key on was plugging in our Dakota Digital VHX gauge cluster and clock assembly. We've been very impressed with Dakota Digital's VHX line, its looks, and compatibility with the factory ECM. The info display in the VHX cluster will receive any warning signals from the computer, and display them where the odometer would normally be displayed on the cluster (in the photo it says CHECK ENGINE). This means we'll know instantly if there are any issues. Once rolling we'll calibrate the speedo with the built-in GPS calibration function, and everything will be all set.
27-28. And there you have it, our 5.3L/4L60E combo is installed and ready to go. On the dyno, the 5.3L was putting out 271 horsepower and 317 lb-ft of torque. Much better than the maybe 100 ponies the car had at the same wheels, plus the reliability and economy of fuel injection. And with the 5.3L V-8, we have a very high ceiling of performance mods we can install to up those power numbers.