Jeff knew right off the bat that he wanted LS power for his flyweight creation, and found a 5.3L from a wrecked '04 Buick Rainier for the fire sale price of $800. The Rainier's optional all-aluminum LM4 had a factory power rating of 290 hp, which would've been more than enough for such a light car, but Jeff figured that a few choice take-off parts he had lying around couldn't hurt, so in went a discarded LS7 cam, a $35 Craigslist Corvette LS1 intake manifold, and a cable-actuated 75mm Camaro throttle-body. By the time Jeff upgraded the valvetrain hardware with Patriot valvesprings and keepers, and added a '02 Camaro ECM programmed with HP Tuners software, the little 325ci bullet was belting out 400 hp for about a quarter of the price of a GMPP E-Rod crate motor.
Fitting the Rainier's LM4 in the Vega provided some interesting insights into the Vega's construction-or lack thereof. Using a Camaro LS1 bare block as a template, Jeff came to a more realistic understanding of the Vega's unibody design. "We had to seam weld all the sheetmetal, like in the inner-fender aprons," Jeff says. "I had it on the two-post lift and used an empty LS block to check out the oil pan clearance with the steering. I had it set up where I had the perfect amount of clearance when it was on the ground. Then, when I lifted it into the air, it flexed all over the place. The oil pan clearance went from a quarter of an inch to an inch and a quarter-with only an empty block in place. That's what prompted me to seam weld everything."
Gone is the Vega's stock 140ci aluminum inline four-cylinder, and in its place resides a 5
Otherwise, getting the LM4 shoehorned into the Vega's engine bay was pretty straightforward. Jeff fabricated most everything, including engine mounts, the trans crossmember, the suspension's tubular control arms, and engine bay braces. The stock Buick exhaust manifolds worked fine, and Jeff says without their heat shields, they even look like little cast headers. The heater box was flipped over to move the coolant couplings outboard for extra room, and a slick air inlet tube was fabricated from fiberglass sheet, epoxy resin, and a home-brewed lost-foam mold method. A Be Cool radiator is one of the only splurge points. ("They actually make one to fit an LS swap into a Vega!" Jeff says.)
The budget theme continues at the trans, which was a discarded Turbo 350 three-speed automatic rebuilt by his accomplice, Ralph Babineau. The decision to forgo any overdrive was based on cost, namely the zero price tag of the Turbo 350, and the fact that it fit perfectly. After the freshening, it was mated to a 10-inch B&M converter and the Vega's stock shifter. For the road course and gymkhana work Jeff had in mind, the Turbo 350 worked out perfect: "You can put the trans in low, and run these Goodguys AutoCross courses in the perfect gear. Throw it in low and go!"
Most economy cars from the '60s and '70s had lowly leaf-spring rear suspensions underpinning them, but Vegas had a superior triangulated four-link similar to the GM A-body. (Later models of the H-platform, starting with the '74 Vega, had a torque arm.) This made beefing up the Vega's rear suspension a matter of replacing the stamped dog bone control arms with tubular control arms that Jeff fabricated in his shop. The stock rearend wouldn't do, so he went searching for a suitable alternative, and found one in a '99 Chevy S-10 Xtreme pickup-which became the donor for several other cool parts. The 8.5-inch 10-bolt in the Xtreme happens to be the right width for the Vega, and came with the 3.42 gears, sway bar, and disc brakes that Jeff needed. All he had to do was fabricate the control arm mounting brackets and swap in a Detroit Truetrac differential. The Xtreme pickup also donated its front spindles and front disc brakes to the Vega, giving it a completely modern, low-cost brake system that works like a charm.