Topping this big-block, we utilized a single-plane, aluminum intake manifold from Indy Cylinder Head with a Holley 4500 series Dominator carburetor flange. An engine this size definitely needs an appropriate amount of fuel and air to run properly, and the Indy intake matched with a 1050 cfm Dominator carb will provide a good baseline for this engine. In reality, an engine of 535 inches may like a larger carburetor and could even benefit from dual carbs. But for the purposes of this build, the 1050 will allow us to dyno the engine, and get an idea of the power it will make. Once installed in Jim's 'Cuda, we'll likely try a variety of carburetors on the big-block to optimize the combination.
With our big-block assembled, we bolted it to the Superflow dyno at Auto Performance Engines to tune it and measure its power output. An engine dyno doesn't just determine the power and torque an engine makes, it's also a useful tool when it comes to experimenting with different timing and carburetor specs, and is a nice way to check for leaks or problems prior to bolting the engine in a car. With our engine warmed up we applied a slight load on the dyno servo to help seat the rings, then made a partial power pull to check the engine under a full load. The big-block sounded powerful, making respectable power and torque on the short pull, so we pulled the oil filter to check for contamination and checked valve lash prior to making power pulls. Finding the valve lash to be just where we had set it and no excessive metal in the oil filter, it was time to tune this engine and see what kind of power it would make.
With the ignition timing set with a conservative 33 degrees of total advance (17 degrees at idle), our first pull to 6,000 rpm netted more than 640 lb/ft of torque and 676 horsepower. Increasing ignition timing and carburetor jetting netted additional power, and peak horsepower was achieved at a leisurely 6,600 rpm. With peaks of 642.5 lb/ft of torque and 705.3 horsepower, this engine should easily propel the '72 'Cuda to sub-ten second elapsed times, while remaining reliable and durable. To see videos of this engine running on the dyno at Auto Performance Engines be sure to visit our website, moparmuscle.com, and look for updates in future magazine issues to see how the car performs at the dragstrip.
07 We used Cometic multi-layer...
07 We used Cometic multi-layer steel head gaskets for this application, which require a smoother deck finish than regular composite head gaskets.
08 With the ARP head studs...
08 With the ARP head studs tightened to the proper torque, we installed the Jesel mounting plates and rockers, and set valve lash. The Jesel rocker system is slightly more complex to install, but will ensure valvetrain stability even after many dyno pulls and dragstrip passes.
09 We topped this big-block...
09 We topped this big-block with Indy's 440-14-3 single-plane intake manifold and a Holley 1050 cfm Dominator (4500 flange) carburetor. This combination will provide great power, and the simplicity of a single four-barrel. At the track, the owner of this car may try larger carburetors or even multiple carburetion to optimize the package.
Price Tag
|
| Indy 440-1 CNC345 cylinder heads assembled | $4,058.00 |
| Jesel Rocker arms | $1,499.00 |
| Indy 440-14-3 Intake | $399.00 |
| Holley 1050 cfm Dominator Carb | $947.78 |
| Machine Heads for Jesel rockers | varies by shop |
| Dyno Time | varies by shop |
Cylinder Head Flow Table
|
| Lift | Intake flow | Exhaust Flow |
| .200 | 154.5 | 127.1 |
| .300 | 235.9 | 171.2 |
| .400 | 295.1 | 207.3 |
| .500 | 329.7 | 233.5 |
| .600 | 347.4 | 254.8 |
| .700 | 354.9 | 268.0 |
| .800 | 356.1 | 280.0 |
*Remember, each flow bench is slightly different; these numbers are used as a reference and could vary depending on what shop flows the heads and what flow bench is used.10 We initially jetted our Holley 1050 with size 90 jets in the front and rear, but eventually jetted the carb all the way up to size 96 jets to optimize the air/fuel ratio. It is not uncommon for a big wedge like this to utilize 96 or even larger jets as these engines need an abundance of fuel to make their power.
11 We were hoping for more than 700 horsepower from this combination, and we achieved it with power to spare. Even better, peak horsepower was obtained at a leisurely 6,600 rpm, ensuring this engine will last a good long time before needing to be freshened up. Check out the power and torque this big-block made. These numbers should easily propel Jim Freed's '72 Plymouth 'Cuda to sub-ten second elapsed times in the quarter mile. Be sure to check out our website for videos of this engine making dyno pulls.