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Budget Chevelle LS Engine Swap

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The performance world is full of stories on how to bolt in a $10,000 crate LS engine into a 100-point, perfectly restored muscle car. The majority of these well-meaning stories seem to miss the mark with regard to budget. For many car crafters, the cost of a new crate engine alone would send their projects into crippling budgetary crisis. Worse yet, the stories seem to gloss over the details that, for the DIY guy, are the real meat of the story. What engine mounts did they use, and is there more than one option when it comes to oil pans and headers? What if you don't want to spend $2,500 on an accessory drive? These and a couple of dozen additional details are what we will cover here. Granted, this story is specific to stuffing a budget-friendly LS truck engine into our Orange Peel '66 Chevelle, but many of the details that surround this conversion will help you with a similar swap into an early or second-gen '68 to '72 Camaro or Nova, or even into a Buick Special, Olds Cutlass/F-85, or Pontiac Tempest.

Engine Quest

Our journey began when we ran across a well-used 5.3L truck engine for sale on Craigslist for $200. The seller had yanked it in favor of a larger 6.0L engine, and his take-out was exactly what we were looking for. The engine came as a long-block that was missing the intake manifold but came complete with the heads, front and rear covers, valve covers, and even the spark-plug coils. We dragged it home, removed the heads, cleaned the block exterior, and then painted it an appropriate Chevy orange. The stock LS truck cathedral-port heads are, other than chamber size, virtually the same in terms of port volume, valve size, and intake and exhaust port flow. Stock truck 4.8L, 5.3L, and 6.0L truck engines sport similar compression ratios that hover around 9.5:1. This is in deference to 87-octane fuel and high loads. We decided to use an inexpensive Fel-Pro composition head gasket that measures a thinner 0.040 inch to help raise the compression to 9.75:1. Next, we installed a new Comp hydraulic roller cam, and just before bolting the heads back on the engine, we decided to double-check the stroke to ensure we had in fact purchased a 5.3L engine. Because the 4.8 and 5.3 share the same small 3.78-inch bore, we rotated the crank to put the piston at the bottom of its bore and used a dial caliper to measure the piston travel. When the caliper read 3.27 inches, we realized we'd been duped. If the engine had been an actual 5.3L, the stroke would be 3.62 inches. This really didn't change anything as far as our engine swap was concerned, but dropping from 325 to 293 ci certainly puts a dent in both torque and horsepower. While we were shooting for 375 hp from the 5.3, we've lowered our expectations to around 315 hp and less torque. Bummer.

But this small setback doesn't really change the purpose of this story, which is to chronicle all the details necessary to complete an LS engine swap.

Cam Specs

Comp Camshaft 269LR HR-112Duration (Advertised)Duration (0.050)Lift (inches)Lobe-Sep Angle
Intake2682190.607112
Exhaust2762270.614

Oil Pans— What Fits?

This is our second swap of an LS engine into our Orange Peel '66 Chevelle, and we're still learning new stuff. We wanted to use the new Holley cast-aluminum pan on this application, but apparently it's a popular item and was back-ordered, so it missed our engine installation deadline. Instead, we used a Champ LS1 swap pan, which fit very well. One issue we had with all of the pans was that the wider Comp Cams timing chain required a spacer to clear the oil pump. This didn't appear to be a problem until we tried bolting on the oil-pump pickup. Because the oil pump was now relocated 1⁄4 inch forward, we had to elongate the pickup mount to make it fit.


Dropping the motor into the car is always a fun part of the adventure. Car Craft family member Kris Shields helps guide our budget LS into the bay.

Our iron-block LS truck engine came via a Craigslist ad for $200 that we snapped up too quickly. We should have yanked the heads to double-check the displacement, as we later discovered it was really a 4.8L motor. Checking the stroke is the best way to differentiate the 4.8 from 5.3 motors.

Once we removed the heads, our first step was to access the cam. After building our first LS engine a few years back, we invested in this Posi Lock three-jaw gear puller (PN 104) from Sears. There are no boltholes in the balancer for a normal balancer puller. The Posi Lock jaws fit perfectly into three flats on the back side of the OE balancer. It will also remove crank timing gears.

We chose a mild Comp 216/227 duration at 0.050 camshaft, since our engine was challenged in the displacement department. The big advantage besides adding duration is the cam's impressive 0.600-plus valve lift numbers.

We reused the stock lifters after carefully cleaning them and checking the rollers for any hint of damage. The guys at Crane once showed us how to check for roller damage by slowly rolling each lifter over the inside of your forearm. This sensitive part of your arm will detect catches or flat spots that signal imminent problems.

The heads must be removed to service the lifters, so we took the opportunity to swap to a thinner and less expensive Fel-Pro composition 0.040-inch gasket to bump the compression to 9.75:1.

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