One trick piece used by Promax...
One trick piece used by Promax was this billet timing cover kit, allowing camshaft timing changes by just removing the water pump and small cover over the camshaft.
To top their 440 short-block, Promax was required to use the same Indy SR cylinder heads as the rest of the competitors. Rather than porting their heads to Max-Wedge port dimensions for maximum flow, Promax opted to keep the same port dimensions as factory 906 heads because too much port volume wouldn't match the rest of their combination. Of course the heads were treated to bowl blending, and ported to the extent possible while retaining the factory port openings, then treated to a multi-angle valve job, stainless steel valves, and new Comp Cams roller valvesprings. Harland Sharp roller rocker arms were employed to actuate the valves. For induction, Promax again would like to thank a generous customer who allowed them to use a Weiand high-flowing Six-Pack intake manifold. While most Six-Pack intake manifolds are limited by their dual-plane design, the Weiand unit has a raised open plenum, making it a better choice for peak power. To mix the air and fuel, a trio of Promax prepped Holley two-barrels were utilized. Having special metering plates allowing jet changes in the outboard carburetors, the Promax Six-Pack carbs pretty much set the standard for three deuce tuning.
|Indy Cylinder Head||Schurbon Engine and Machine|
|Indianapolis, IN 46239||Maquoketa, IA, 52060|
|JMS Racing Engines||JD Engine and Machine|
|El Monte, CA, 91732||Columbia, MO, 65203|
|Chenoweth Speed and Machine||Cederstrand Racing Engines|
|Morton, IL, 61550||Brea, CA, 92821|
|Indianapolis, IN 46222|
No real tricks were used in...
No real tricks were used in this engine, just solid building techniques. Even the water pump was driven at a one-to-one ratio.
Promax used the same Indy...
Promax used the same Indy SR aluminum cylinder head as the rest of the field, but chose not to increase the port height to Max-Wedge size due to their intake selection and relatively mild engine.
The chamber of the Indy SR...
The chamber of the Indy SR cylinder heads, combined with Diamond flat-top forged pistons, gave the Promax entry a relatively mild ten-to-one compression.
Harland Sharp aluminum roller...
Harland Sharp aluminum roller rocker arms actuated the stainless steel valves. A Comp Cams solid roller camshaft and matching springs were also used in this engine.
An MSD Pro-Billet electronic...
An MSD Pro-Billet electronic distributor handled the ignition duties, keeping all the cylinders lit all the way through the 7,000 rpm requirement of the contest.
Promax is known for their...
Promax is known for their innovative Six-Pack carburetor systems, so it was no surprise that triple Holley two-barrels adorned their engine.
Promax manufactures their...
Promax manufactures their own metering blocks and plates for Mopar Six-Pack carburetors, making these carbs easy to tune for any combination.
The real unique features of...
The real unique features of this engine were in the induction system. Promax borrowed a customer's Weiand intake, a high-rise open plenum unit that hasn't been produced in many years, as a basis for their trick induction system.
A longtime problem of factory...
A longtime problem of factory Six-Pack induction is that the outboard carbs don't have metering jets, making them hard to tune. Promax has solved this problem by manufacturing custom, billet metering plates with changeable jets. If you're running a Six-Pack on your Mopar, we highly recommend calling Promax about this upgrade.
Typically, Six-Pack tuning...
Typically, Six-Pack tuning changes would have been difficult in the time our contest allows between dyno pulls. Thanks to the modified Promax carbs, these guys had plenty of time for jetting and tuning their engine.
As a late entry, Promax was...
As a late entry, Promax was at a definite disadvantage in this year's challenge. We thank them for their participation and congratulate them on making 554.1 hp and 526.3 lb/ft of torque for a seventh-place finish in the 2008 Engine Challenge.