Westech Performance 496 Chevy Big Block Build - A Monster Is Born

To gain easy access to the cam in case of timing adjustments, this two-piece cover (PN 219) will give us access to adjust the billet timing set (PN 810) without having to disrupt the oil pan seal.

Brul needed to clearance the Wiseco 48cc domed set of pistons from the spark plugs. On the mill, 0.170 inch was notched out to ensure there was enough distance from the dome to the electrode.

We used the supplied Wiseco ring package that measured in at 1/16, 1/16, and 3/16 inch. And because the 496ci mill featured 12:1 compression, we went ahead and set all of the top rings at 0.022 inch of clearance.

When it came to the oiling system, Brul opted for a complete Milodon setup, including the high-volume pump with the extreme-duty pickup, along with the oil pump shaft (PN 23060).

With so much stroke from the swing of the crank, it's necessary to clearance the scraper in order for the rotating assembly to pass freely. Brul took his time and it shows. These notches are textbook perfect.

Proper oiling is critical and a starved motor can self-destruct in a matter of seconds. Milodon's pan controls this through baffles, provides consistent oil pressure, and prevents any power robbing oil movement. Our piece (PN 30955) features an 8 1/2-inch-deep sump and with a filter provides 7 quarts of oil.

Keeping the cylinder heads in place is a set of ARP fasteners (PN 135-3707) that were torqued to 75 ft-lb. Brul began in a traditional clockwise fashion, starting with the center and working his way out.

We laid down gaskets with the two-piece rear seal adapter from GM and planted the oil pan down. After the pan was on, we rolled over the rotating assembly to ensure that neither the crank nor the rods were colliding with the inside of the pan.

Sandwiched in between the carb and intake was a Comp open spacer. What exactly does this spacer do? It provides better atomization of the fuel and air, which in turn means more power for the big-block mill.

An Edelbrock Victor Jr. 454-R was used to provide the atomized fuel and air charge to our AFR 325s. A Holley 1,000-cfm carburetor was chosen because of its excellent out-of-the-box characteristics and performance.

Handling the spark is a MSD billet distributor and wires. After a 20-minute break-in session, we were ready. Final peak numbers came in at 36 degrees total timing.

1.Fel-Pro top-quality sets include Perma Torque preflattened, steel-ring head gaskets and Printoseal intake manifold gaskets to keep our mill sealed.
2. Comp Cams pushrods feature a 3/8-inch ball. They spec'd out at 8.580/9.470 intake/exhaust (PN 7906-8/7757-8).
3. 1.7:1 Pro-Magnum roller rockers have 5 percent less weight at the valve than most aluminum rockers. This means more rpm and valvetrain stability. Our set was lashed at 0.026/0.028 intake/exhaust.
4. The 8-inch damper will keep our big-block's balance in order.