Since there were no acceleration forces on the dyno, the LaRoys chose a stock 4 quart oil
Starting with a factory 400 block, LaRoy Engines had all the necessary machine work performed to accommodate a forged Chrysler 440 crankshaft and Ross forged flat-top pistons. Scat forged H-beam connecting rods were used for their strength and relative light weight, and Total-Seal piston rings were used to seal the cylinders. The rotating assembly was balanced and a Professional Products SFI-approved damper was utilized. An Erson roller camshaft was matched to a set of Comp Cams solid roller lifters for well over .700 inch of total valve lift, and a power curve that was still increasing at the 7,000 rpm limit of the competition. To handle engine lubrication, a Melling high-volume oil pump was utilized along with a stock, 4-quart oil pan, and Jim LaRoy fabricated a crankshaft scraper from a stock windage tray.
Edelbrock Performer RPM cylinder heads were the required heads for this year's challenge, and our rules allowed pretty much any modification other than welding the heads or moving the rocker location. LaRoy Engines specializes in cylinder head porting, and Cody LaRoy worked his magic on these cylinder heads, netting an amazing 349 cfm of flow at .800 lift on the intake side. Even more impressive, these flow numbers were accomplished with no epoxy modifications whatsoever. In addition to porting, these heads were cut to accommodate 2.25-inch Manley stainless steel intake valves and Comp Cams PN 951 valvesprings with titanium retainers. 440Source supplied the 1.6 ratio roller rocker arms, and a used Indy 4500 flange single-plane intake was matched with an 1,150 cfm Pro Systems Series XC carburetor. Ignition was handled by a Summit Racing electronic distributor wired to the dyno's MSD ignition box.
....windage at a minimum. To help, a crank scraper was fabricated from a factory big-block
Located in Indianapolis, Indiana, the racing capital of the world, and with an address right on Gasoline Alley, ProMax Performance is no stranger to powerful engines. While they began as a carburetor shop known for tuning, modifying, and manufacturing single and multiple carbs and parts, ProMax now offers an array of services including engine building and dyno testing. Owner and engine builder Ben Gorman loves the automotive industry, and he and his employees campaign three active Mopar race cars as well as sponsoring the ProMax fastest street car shootout. For this year's contest, ProMax built an economical 451-inch big-block, making nearly 570 horsepower for a fourth place finish.
On the dyno, the ProMax entry performed flawlessly, making all of its pulls with ease. Starting with 36 degrees of ignition timing, the ProMax crew quickly tuned their engine to additional power by bumping timing to 38, then 40 degrees of total advance. During their qualifying and judged pulls, ProMax utilized one of their blueprinted Holley 850 carbs to show the potential of their product. After their best pull of 568.9 horsepower and 518.1 lb/ft of torque, Ben changed to a Holley 950, losing power and torque across the board. We've always known these guys have a knack at tuning and building carbs, and the dyno backed up our opinion.
Edelbrock-installed exhaust valves were used in these heads, but the intake seats were cut
Using a factory Chrysler 400 block as the basis for this engine, ProMax machined the block for a stock 440 crank, giving the engine a stroke of 3.75 inch. Diamond PN 52007 forged flat-top pistons were hung on Eagle forged steel H-beam connecting rods, and the rotating assembly was balanced. Clevite engine bearings and Total Seal piston rings were utilized in this engine, along with a PRW PN 2444001 SFI approved balancer. A Melling PN M63HV oil pump was combined with a factory Hemi oil pan and Milodon windage tray to keep the engine sufficiently lubricated. Comp Cams' PN 23-362-5 flat-tappet camshaft was used with Comp solid lifters, spun by Comp's PN 2104 double-roller timing set. A factory Chrysler electronic distributor was used to ignite the mixture, performing flawlessly to 7,000 rpm.
Looking from the carb flange of the intake down the runner, the detail of the extensive po
A combination of Harland-Sharp and 440 Source 1.6 ratio aluminum roller rocker arms were u
The ProMax Performance entry was a strong contender, making 568.9 horsepower and 518.1 lb/
ProMax machined their 400 block for a factory 440 forged crankshaft, then added Diamond fo
With tough forged internals, this engine was built to last, Total Seal piston rings and Cl
Staying away from an expensive roller cam and the cost of the associated valve gear, ProMa