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383 Short Block Engine Build - Open-Box Policy

GMPP's 383 Short-Block Serves As The Foundation For A Complete Brodix Top-End Kit

Sean Haggai Aug 1, 2009
0908chp_01_z 383_short_block_engine_build Performance_engine 2/17

Our bang-for-the-buck mentality can lend to a host of great ideas and combustive mixtures for making super power on short coin. Don't get us wrong--we love a great custom engine combination making freight-train steam that sends the earth's rotation twisting in the other direction. However, we also still have an affinity for proven short-block combination builds. For the street, our theory for boxed engines has yet to be questioned.

It was important to begin our build on solid ground. GM Performance Parts (GMPP) might as well be called Engines "R" Us, because its catalog is basically a toy store for the itchy automotive soul. Our insatiable appetite for GMPP's ready-to-go short-blocks made the company an easy choice for cost-effective power. The offerings range from sedate two-bolt main 290hp 350s and more muscular and complete 383 turnkey engines to the baddest of the bad, such as the 720hp 572ci big-block. Now, we can't help but get our hands dirty, and the 383 carries the best of both worlds for the street. While we appreciate GM's willingness for drop-in-style turnkey motors with all the bells and whistles, we also wanted to take full advantage of Brodix's new top-end kit.

There we opted for the 383 short-block crate engine (PN 12499106) for a solid foundation. This assembly features a four-bolt main with a one-piece rear main seal, the perfect starting point for solid, reliable power in a box. Inside resides a forged 4340 steel 3.800-inch stroker crankshaft, heavy-duty 5.700-inch connecting rods, and hypereutectic dished pistons--needing only a valvetrain and top end to complete the engine.

For just about $1,950, Brodix will pull out complete matching aluminum 200cc intake runner cylinder heads and a dual-plane manifold combo unlike any other. While the heads come standard with 64cc chambers, we had Brodix mill them to 58 cc (additional $212), bumping the compression ratio. We also took advantage of the CNC combustion chambers option, which added $227 to the tab. Even at 58 cc, pump gas is still a reality with this kit, plus Brodix makes sure to supply everything needed to button up the top end.

What's more is our Comp valvetrain took full advantage of the Brodix package. The Comp 'stick we chose came with 242/248 degrees of duration at 0.050 and 0.540/0.562 inch lift on intake/exhaust. We even topped the valvetrain off with Comp's newest member, the Ultra-Pro Magnum roller rockers with a 1.52:1 ratio.

As usual, we followed the build at Westech Performace Group, as Steve Brul put up the wrenching. We threw in the Comp goodies, bolted on the Brodix top end, installed a Holley 750, and strapped the 383 to the dyno to get the numbers all in one day. Our combo was good for 466 hp and 456 lb-ft, and we even ran the mill to 7,000 rpm to showcase its upper-rpm potential. Read on to see how we pulled it off.

Quick Notes
What We Did
Pieced together a reliable yet potent 383 combo for the street

Bottom Line
It's a stump-puller from 3,000 rpm on up

Cost (Approx)
$2,400 for top end, $6,035 bottom end

0908chp_03_z 383_short_block_engine_build Diagram 9/17

1. Brodix dual-plane manifold with 4150 carb base fitted with Holley 750-cfm carburetor. Kansas-like torque curves for everyday grunt and upper-rpm flexibility were abundant.
2. The camshaft took advantage of the Brodix 200cc heads. We swapped out the springs, locks, and retainers to avoid valve float and to increase our rev potential. We swapped in Comp springs (PN 26120), locks (PN 795-16), and retainers (PN 613-19) for more open/closed seat pressure.
3. Comp 7.300-inch-long pushrods (PN 7949-16) push the Comp hydraulic rollers we have in place with H-bars. The pushrods are heat-treated chromoly with 0.080-inch wall thickness.
4. As usual, we relied on a Pro-Billet MSD ignition distributor (PN 85551) and wires.
5. Expelling fumes were Hedman 1 3/4 x 3 1/2-inch dyno headers with 18-inch collectors.

Build List
Our foundation was a GM 383 short-block assembly (four-bolt main block, forged crankshaft, hypereutectic pistons, 5.700-inch rods, 8-inch harmonic balancer, 12 3/4-inch flexplate, windage tray, 5-quart oil pan, composite timing cover).

The top-end kit included 200cc cylinder heads, clean and blended bowls, CNC combustion chamber, angle milling for increased compression, matched intake ports, 2.20/1.600-inch intake/exhaust valves, dual-plane intake manifold, valve covers, intake gasket, 4150 carb gasket, STD port exhaust gasket, NGK B8ES spark plugs, head bolt kit, intake manifold bolt kit.


Westech Performance Group
Mira Loma, CA
Mena, AR 71953
Chevrolet Performance Parts
Detroit, MI 48232
Ashland, MS 38603
Memphis, TN



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