540 Chevy Big-Block Engine Build - Toeing The Line

Besides providing excellent flow figures, Brodix Race Rite heads are drilled to accept stock accessories and brackets; the exhaust ports are also located in the factory location, making manifold or header installation a snap. From a performance standpoint, the RR BB-R heads are CNC port-matched and bowl blended, and feature a competition valve job.

Our bumpstick for this project was a Comp XR282R solid-roller, sporting 0.653/0.660-inch lift and 248/254 degrees durations. The cam card called for installation to be on a 106 intake centerline-Shoemaker degreed the cam and found that it spec'd in at a 105-degree intake centerline. We call it close enough, especially after the timing chain stretches a bit.

According to GM, Gen VI blocks feature a reinforced deck surface for better sealing. To use Mark IV heads on a Gen VI block, the proper gasket must be used-in this case, we employed Fel-Pro 1075 MLS gaskets.

In addition to its CNC gasket-matched, 294cc intake ports, Brodix's Race Rite BB-R heads feature 119cc CNC bowl-bended combustion chambers.

Shoemaker fastened the Brodix lungs in place with ARP head bolts, using moly lube on the threads and under the washers. Torque was 70 ft-lb. When one is using MLS gaskets, Shoemaker told us, final torque needs to be rechecked several times, since the gasket may move as many as four times before it takes a set at the final torque value.

Once the heads were bolted into place, Shoemaker set up the pushrods and rocker arms on one cylinder to check piston-to-valve clearance. Shoemaker does this by bringing the piston up to TDC, zeroing the dial gauge, then tightening the rocker bolt and compressing the lifter until the valve touches the piston. We had more than 0.130 inch clearance on the intake side and more than 0.155 inch on the exhaust.

We used Manley rocker studs and pushrod guides as the foundation for our valvetrain. Shoemaker noted that the stud holes in this setup aren't blind, and therefore need to be coated with thread sealant.

With our Manley pushrods and Comp Pro Magnum 1.7:1 rocker arms in place, Shoemaker set the valve lash. The hot setting on the cam card is 0.016/0.018-inch intake/exhaust. Shoemaker set the cold lash 0.006 tighter (0.010/0.012 inch) to compensate for the expansion that will happen as the engine heats up. The lash was rechecked once the engine reached operating temperature, of course.

The holes are used when installing an OEM intake manifold. They weren't used in our setup, so Shoemaker filled them up with some silicone before putting the intake gaskets in place.