Video: SAM Engine Masters Challenge Chrysler Poly 402ci On The Dyno!

The Engine Masters Challenge is a showcase for engine builders throughout the land to put their skills on full display in front of the masses; each year the competition brings the best of the best to one place with their latest developmental projects. This year there are five separate classes: Hemi Showdown, Vintage V8, LS vs. Modular, Spec Small-block, and Unlimited.

The School of Automotive Machinists has been competing in the event for the last several years, with excellent showings using a variety of engines. The event takes place next week — October 5-9, 2015, at the University of Northwestern Ohio — and has the SAM team, led by instructor Judson Massingill, set to compete with a 402ci A-Series Chrysler engine topped off with a set of the long-maligned “Poly” cylinder heads in the Vintage V8 class.

Other engines permitted in Vintage V8 competition — which are engine families introduced in 1954 or earlier — include the Nailhead Buick, Y-Block Ford, and Packard V8.

(Left) The assembled short-block waiting for top-side components. (Middle) Note the use of the camshaft belt-drive and the belt-driven distributor -- two items that didn't even exist when this engine first hit the showroom. (Right) The Polyspherical cylinder heads are the forerunner of the later world-beating Hemi heads.

“This engine gets a lot of attention, that’s for sure. There’s an underground for these that we’d never heard about. It has a fairly decent head, and we set it up with the conventional exhaust with a raised runner intake port,” says Massingill.

IMG_3149The 402 ci engine is based around an OE block and set of cylinder heads that have been machined and assembled by SAM students in their Houston facility. It consists of a 3.950-inch bore block filled with an Eagle 340 LA-series 4.000-inch stroke forged crankshaft that’s been offset-ground to 4.100-inch and finished with small-block Chevy rod journal dimensions, a set of Carrillo connecting rods, and an octet of CP pistons.

“The 318/340/360 engine is based off this block. The 340 crank bolted right into this engine; housing bore, spacing, and all of that was the same,” he says.

The SAM students wouldn’t be able to complete any of this work on their own without the assistance of the instructors that are hand-picked by Massingill. All of the short-block assembly processes were performed at the direction of instructor Chris Bennett, while Shawn Hooper oversaw cylinder head development and Jonathan Waitt made his mark on the project by coordinating all of the CNC work.

The induction system on this beast is different from the “standard” four-barrel carburetor — Holley‘s Dominator EFI controls a set of Hilborn EFI stacks, while a Comp Cams bumpstick and T&D shaft-mount rocker arms get the Ferrea valves pumping up and down in the cylinder heads.

“When people think about Hilborn, they think mechanical injection, but this is their EFI system controlled with the Holley EFI engine management system. We didn’t have any tuning challenges at all — it just came right in. The hardest part was making it work on the dyno to control the individual runners. In fact, Hilborn didn’t even make a system for this engine; they sent us the bare basics and we had to machine our own bores into the housings, then used a plate to make them match up with the heads,” Massingill explains.

The Hilborn EFI system needed 'massaging', but the SAM students were up to the task. Super-long inlets have been fitted to solidify the power in the intended operating range.

The Polyspherical cylinder heads are certainly a departure from the normal small-block Chrysler architecture. Unlike the later wedge-head design of the LA-series engine family, the A-Series cylinder heads use a canted-valve layout that’s very similar to race heads of today, and are in fact the forerunner to the later Hemi heads.

Ancillary parts are from Mahle/Clevite, Fel-Pro, Total Seal, ARP, and Cometic.

The engine produces peak torque and horsepower near 1.5 per cubic inch, although Massingil wouldn’t disclose the final power figures, telling us that we’d just have to wait until the engine hits the dyno at UNO next week. He assured us they’d be competitive, although they’ll face stiff competition from a Y-Block engine built by none other than Jon Kaase, among other tough challengers.

“We made the stacks as long as the rules allowed. On this thing, we run it from 3,000-6,000 rpm, so any power after 6,000 is of no use to us. We’re trying to make as much power as possible as quickly as possible,” he says. “The students really enjoyed working on this unique engine.”

In addition to this project, which will hit the dyno on Day 4 of the competition, the School of Automotive Machinists will also be competing in the LS vs. Mod Challenge with two separate induction packages. The rules for that class force the competitors to show up with their own induction designs and run them on a spec short-block.

For more information on the School of Automotive Machinists, check out their website.

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Jason Reiss

Jason draws on over 15 years of experience in the automotive publishing industry, and collaborates with many of the industry's movers and shakers to create compelling technical articles and high-quality race coverage.
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