Rebuilding a Factory-Correct 427 Big-Block - Engine of Desire

Making what's old new again, in Jasper's Authentic Custom Drivetrains Division

Steve Temple Mar 7, 2014 0 Comment(s)
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For owners of classic Corvettes, replacing a beloved, original engine might feel akin to cutting out your heart. Sure, transplants are fine for restomod projects that pound the ground with a modern LS powerplant. But what if your car is a survivor, or a pristine restoration?

Brad Ryan's '67 coupe fits mostly in the former category, a fully loaded older Vette that Ryan prefers to keep pretty much as it was from the factory. So when the car's 390hp, 427ci engine began pushing some oil—partly from sitting still, partly due to Ryan's heavy right foot—"I put it away before I blew it up," he admits.

It wasn't long, though, before Ryan began searching for a company that could remanufacture the historic big-block. He wasn't looking for a simple rebuild/refresh (which he had personally done once before), but rather a return to original specs, or even better.

This desire led him to a special division within Jasper Engines and Transmissions: Authentic Custom Drivetrains. Founded in 1942, Jasper is known for remanufacturing large volumes of drivetrain components—about 57,000 gasoline engines per year, along with 68,000 transmissions and 9,500 differentials. But upstairs from this massive operation is a newer, limited-volume (350 to 400 units per year) area devoted to rescuing treasured, collectible powerplants (plus transmissions and differentials) from the brink of oblivion.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire Brad Ryan And 2/21

Here, veteran technicians who have an appreciation for the pride and satisfaction that accompanies classic-car ownership painstakingly bring back drivetrains from a near-death state. The process consists of a numbers-matching build, original paint, testing, and, for an upcharge, valuable documentation of the remanufacturing process. That way, should a classic Corvette or other collectible car ever be sold, the owner can prove the lineage and meticulous care that has gone into the project, preserving its historical value.

This optional documentation package lists in exhaustive detail the bill of materials, specifications, dynamometer reports, and detailed in-process information, including photos. In other words, just about anything you would like to know about your engine as it goes through the company's extensive and precise steps. This information is available 24/7 via a web page, and can also be e-mailed during the hand-building procedure.

When Ryan received a hard copy of the information specific to his engine build, he had this to say: "I was totally impressed with the entire process." Adding to the entire experience, he scheduled a visit to the Jasper facility when the initial firing-up took place, and took great pleasure in hitting the starter button on the dyno panel. "I was really thrilled to hear my Corvette's engine roar back to life."

"It's moments like these that make my job an absolute pleasure," noted Darren Ragsdale, Jasper Authentic Custom Drivetrains & Performance Division Manager. "It's an honor to work on our customers' projects."

Jaspers Authentic Custom Drivetrains Division Engine Of Desire Jasper Main Shop 3/21

01. Jasper’s main shop floor is a sizable operation, covering 367,000 square feet in Jasper, Indiana, with more than 1,500 employees.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire Metal 7/21

05. A metal tag bolted to the heads and block stays on tight during tank cleaning in a heated chemical degreaser, so all the components remain numbers matching.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire Test Replacement 8/21

06. If specific bolts and fasteners can be reused, they’re kept in a basket with the engine for cleaning. If new, replacement parts are made in the same production processes as OE. Testing is performed to manufacturer specs and original production standards.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire 9/21

07. Magnafluxing (magnetic-particle inspection) reveals any cracks or flaws in the casting of the blocks.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire Valve Seats And 10/21

08. Valve seats and guides are machined to exact specifications, or replaced to assure correct alignment and seating.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire Exact Dimensional Tolerances For Every 11/21

09. Every head is resurfaced to exact dimensional tolerances, and the surface finish is carefully monitored for proper sealing with the block.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire Cylinders Made To Exact 12/21

10. Cylinders are bored and torque-plate honed to exact specifications. This eliminates distortion after the head is bolted and torqued to the block, which can otherwise result in blow-by.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire Computerized Dyno Graphs 19/21
Jaspers Authentic Custom Drivetrains Division Engine Of Desire Computerized Dyno Graphs 20/21

17. Computerized dyno graphs document the engine’s output. While horsepower peaks at slightly less than the original gross rating (due in part to a cruise-friendly camshaft selection), the torque number is higher.

Jaspers Authentic Custom Drivetrains Division Engine Of Desire All Work Done By ASE Certified 21/21

18. Jasper provides a parts-and-labor warranty of three years or 100,000 miles (whichever comes first) on most passenger-car and light-duty-truck engines. Ryan’s higher-performance Class 2 engine is covered at one year/16,000 miles for parts, and six months/8,000 miles for labor. All work is performed by ASE-certified mechanics. vette

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